Soils Final

(T/F) A tetrahedral sheet is characterized by a plane of aluminum atoms surrounded by oxygen and hydroxyl groups.

False

(T/F) A, B, C, and E can be found in any true soil.

False

(T/F) Alfisols are found mostly near areas of natural pasture or rangeland.

False

(T/F) Although subsoil is more difficult to obtain, it is generally as good as topsoil for landscaping purposes.

False

(T/F) Except for some kinds of foods, modern industry has made human dependence on soils a thing of the past.

False

(T/F) Isomorphic substitution involved the substitution of a tetrahedral sheet for an octahedral sheet.

False

(T/F) Polysaccharides produced by soil microbes and similar synthetic polymers applied to soils are largely responsible for the crusts that form when rain follows tillage.

False

(T/F) Soil, like concrete and steel, is a standard construction material. Its properties are well characterized and predictable so that standard building foundation designs can be used uniformly at all building sites of a given topography.

False

(T/F) Subsoil is typically equivalent to the O horizon.

False

(T/F) The cation exchange capacity of vermiculite increases if pH increases.

False

(T/F) The water potential in soils is generally considered lower than that in the atmosphere.

False

(T/F) While 2:1 type clays have significant internal surfaces, their external surfaces are generally much more extensive.

False

(T/F) A polypedon, or individual soil, is a group of closely related pedons that conceptually approximates what in the United States is called a soil series.

True

(T/F) Epipedons are diagnostic surface horizons that are one of the primary means of classifying soils in the United States.

True

(T/F) Evaporation from the soil surface (E) is determined to a large degree by soil surface wetness.

True

(T/F) Hydrolysis involves the splitting of water into its H+ and OH- components while hydration attaches intact water molecules to a compound.

True

(T/F) Igneous rocks are formed when molten magma cools and solidifies.

True

(T/F) Isomorphic substitution involved the substitution of one ion for another baed on size.

True

(T/F) Organic matter distribution in the profile is a significant criterion for differentiating epipedons.

True

(T/F) Sandstones are good examples of metamorphic rocks.

True

(T/F) Soil air usually has a higher carbon dioxide content than the air in the atmosphere.

True

(T/F) Soil and crop management generally has a greater influence on evaporation from the soil surface (E) than on transpiration (T) from leaf surfaces.

True

(T/F) Soils classified as entisols have the least well developed profiles of those in any order in the Soil Taxonomy system.

True

(T/F) The broadest category of classification in Soil Taxonomy specifies 12 soil orders, 11 of which are for mineral soils.

True

(T/F) The categories of Soil Taxonomy can be listed from the broadest (first) and most specific (last) as: order, suborder, great group, subgroup, family, series.

True

(T/F) The mineral particles in soil consist of sand, silt, and clay.

True

(T/F) The osmotic potential is dependent upon the presence of salts and other solutes in the soil.

True

(T/F) The polarity of water helps account for the attraction of water molecules for each other.

True

(T/F) The two most significant characteristics of the classification system used in the United States are a unique system of terminology and focus on measurable soil properties as a primary basis for the classification.

True

(T/F) Tillage when the soil is too wet is likely to increase the soil bulk density.

True

20 g of Mg2+ (M.W. = 24) contains how many moles of positive charge? a. 1.7 b. 2.5 c. 17

a. 1.7

An alkaline soil contains 20% clay and 1.5% humus. If the pure clay has a CEC of 40 cmolc/kg and the humus 200 cmolc/kg, calculate the CEC/kg of the soil. a. 11 b. 16 c. 14

a. 11

1 mole of Al3+ contains how many moles of positive charge? a. 3 b. 27 c. 15

a. 3

1 mole of K+ contains how many K+ ions? a. 6.02 x 10^23 b. 12.04 x 10^23 c. 6.02 x 10^46

a. 6.02 x 10^23

"Topsoil" is generally equivalent to which soil horizon? a. A b. D c. E d. C e. B

a. A

Two soil samples, A and B, at different soil moisture levels are placed in contact with each other. Water will more likely move from soil A to soil B if their water potentials, expressed in kPa, are _________. a. A = +5; B = -5 b. A = -5; B = -5 c. A = -100; B = -50

a. A = +5; B = -5

The water in the soil typically differs from pure water because the soil water: a. All of these b. None of these c. contains mineral nutrients. d. contains organic compounds. e. is restrained in its flow by attraction to particle surfaces.

a. All of these

Silicate clay accumulation is most common in the __________. a. B horizon b. A horizon c. C horizon

a. B horizon

If you start with 40 g of soil, and the first hydrometer reading is 27 g/L while the second is 17 g/L, what is the soil texture? a. Clay b. Silty loam c. Silty clay loam

a. Clay

Organic matter is extremely important in the soil and has been called a master variable, why? a. If we change the organic matter type or content in the soil, a lot of other soil properties are affected. b. If we change the organic matter type or content in the soil, nothing else if affected c. While it's present in the soil, it's not very important

a. If we change the organic matter type or content in the soil, a lot of other soil properties are affected

Muscovite mica is an example of a(n) ________. a. Igneous rock b. sedimentary rock c. secondary mineral

a. Igneous rock

Under which of the conditions below will organic matter decay be the fastest? a. Redox measurement > 400 mV b. soil oxygen < 10% c. Redox measure < 320 mV

a. Redox measurement > 400 mV

Two problems associated with this particular issue are poor seedling emergence rates and high runoff rates. What is the problem? a. Soil crusting b. Aggregate flocculation c. Cation bridging

a. Soil crusting

Which of the following disintegration (physical breakdown) processes has the largest effect on rocks a. Temperature b. Plants and Animals c. Abrasion

a. Temperature

Plant roots obtain access to soil water in which of the following ways? a. Water flows to the roots by capillarity. b. Water vapor moves from the wet soil areas to the root surfaces. c. The roots contract and leave room in the pores for the water to move in.

a. Water flows to the roots by capillarity

Argillic horizons are characterized by _________. a. accumulation of silicate clays b. high levels of iron and aluminum oxides c. organic matter accumulation

a. accumulation of silicate clays

Which of the following refer to macropores spaces? a. allow for rapid water movement b. tend to increase the bulk density c. usually filled with water

a. allow for rapid water movement

Practices that decrease organic matter and increase tillage can be expected to most significantly increase the ________ in the soil. a. bulk density b. macropores c. fineness of texture

a. bulk density

Which of the following categories of Soil Taxonomy provides the greatest specificity of soil properties? a. family b. order c. great group

a. family

A mollisol can look like an ultisol but it is different in that it has a a. high base saturation b. low base saturation c. a lot of iron and aluminum oxides

a. high base saturation

Increasing the organic matter content of a soil is likely to _______. a. increase the soil's structure (strengthen the soil aggregates) b. decrease the soil's structure. (disperse the soil aggregates) c. have no effect on the soil structure

a. increase the soil's structure (strengthen the soil aggregates)

Capillarity in soils ____________. a. is dependent of the matric potential in soils b. is enhanced by the symmetrical nature of the water molecule c. involved adhesion but not cohesion

a. is dependent of the matric potential in soils

One of the hydric soil indicators is: a. loss of Fe b. the presence of NO3- c. a long hydroflux

a. loss of Fe

Dull gray colors are characterized by _________. a. low chromas b. mixed hues c. high color values

a. low chromas

If the soil water potential it is due to the absorption of the water to the soil solids, it is which of the following potentials? a. matric potential b. osmotic potential c. gravitational potential

a. matric potential

Which of the following is not a secondary mineral? a. plagioclase feldspar b. montmorillinite c. vermiculite

a. plagioclase feldspar

Septic systems are designed to _______ household waste a. remove and treat b. remove c. back up

a. remove and treat

Igneous rocks can best be characterized as: a. rocks formed when molten magma solidifies. b. rocks formed from the recrystallization of sedimentary material. c. rocks containing a mixture of primary and secondary minerals.

a. rocks formed when molten magma solidifies.

In the Soil-Plant-Air continuum, once the water impacts the soil, it can either infiltrate into the profile or a. runoff b. puddle c. be taken up by the plants

a. runoff

Soils rich in which type of clay would not provide the best site on which to build a home? a. smectite b. Fe, Al oxides c. kaolinite

a. smectite

The expression, P - ET - D estimates the _________ a watershed. a. soil water content of b. discharge volume from c. evaporation from

a. soil water content of

A soil profile consists of: a. the set of layers seen in a vertical cross section of a soil. b. the sum of all chemical and physical data known about a soil. c. the spatial boundaries of a particular soil.

a. the set of layers seen in a vertical cross section of a soil.

Igneous, sedimentary, and metamorphic are three __________. a. types of rocks b. basic classes of soils c. master horizon names

a. types of rocks

You are preparing to buy a lot for a house. While looking over some land you take a few minutes to dig a hole and check for the presence of a/an _______ which would not be a good place to build. a. vertisol b. alfisol c. utisol

a. vertisol

What is the bulk density of a soil with a wet weight of 55 g, a dry weight of 45 g and occupies 35 cm3? a. 1.22 g/cm3 b. 1.3 g/cm3 c. 2.65 g/cm3

b. 1.3 g/cm3

Given that you have 80 g of K+, how many cmolec are present (M.W. of K+ = 39 g, 100 cmolc = 1 mole) a. 400 b. 205 c. 40

b. 205

In a soil with a bulk density of 1.5 Mg/m3, what is the % pore space (Assume Dp = 2.65 Mg/m3). a. 55% b. 43% c. 60%

b. 43%

In a typical mineral soil in optimal condition for plant growth, approximately what percentage of the pore space would be filled with water and what percentage filled with air? a. 10% water and 90% air b. 50% water and 50% air c. 25% water and 25% air

b. 50% water and 50% air

In a given soil, the mineral horizon with the highest organic matter content is generally the _________ horizon (of the choices below). a. E b. A c. B

b. A

Which of the following is true? a. The B horizon is a zone of eluviation b. A mature soil does not need to have all of the master horizons to be considered a soil c. A mature soil profile must have all of the master horizons to be considered a soil

b. A mature soil does not need to have all of the master horizons to be considered a soil

Living organisms can affect the soil profile through a. Profile mixing b. All of the above c. Structural stability d. Nutrient cycling e. Organic matter accumulation

b. All of the above

In soils of which great group would you most likely find wide surface cracks during periods of dry weather? a. Argiaquolls b. Calciusterts c. Kandiaquults

b. Calciusterts

The five soil forming factors are: a. Climate, organisms, time, hydration, erosion b. Climate, organisms, time topography, parent material c. Transformations, weathering, the horizons, topography, and hydrolysis

b. Climate, organisms, time, topography, parent material

Erosion processes consist of three steps: Detachment, Transport, and Deposition. To control water erosion, we must devise methods to stop what? a. Transport of the silt fraction through the water b. Detachment of the silt fraction from the soil aggregates c. Deposition of the sand particles at the delta

b. Detachment of the silt fraction from the soil aggregates

A watermelon grower has asked you for your recommendation on an irrigation method. Based on your experience which of the following methods would you recommend? (Watermelons don't like wet soils) a. flood b. Drip irrigation c. center pivot

b. Drip irrigation

Soils A has a profile with a lot of yellow and red colors while soil B has a prodominately gray profile. Of the two soils, soil A is more apt to be characterized by an abundance of ___________. a. Mn4+ ions b. Fe3+ ions c. S2- ions

b. Fe3+ ions

Using the Feel Method, a soils creates a long ribbon when pinched between the thumb and forefinger. The ribbon is particularly smooth. What is the most likely soil texture? a. Silt loam b. Silty clay c. Clay

b. Silty clay

Based on the figure, which legal land description is correct? a. T19N, R11W, sec 12, NW1/4 b. T19N, R15E, sec 28, SW1/4 c. T19N, R15E, sec 15, NW1/4, E1/2

b. T19N, R15E, sec 28, SW1/4

You are consulting with a farmer about their plans for the next few years. You have Web Soil Survey open and notice that one of the fields has a Bg horizon 12" depth with a predominantly grey background. From this information, you conclude which of the following? a. The soil is somewhat poorly drained but the crops to be grown are hardy and can take the water b. The soil is poorly drained, the crops to be grown should be chosen carefully c. There are no limitation to crop growth.

b. The soil is poorly drained, the crops to be grown should be chosen carefully

What drives the Soil-Plant-Air Continuum? a. Root suction b. Water potential c. Solar radiation

b. Water potential

A subsoil that has both a "g" and a "t" subordinate distinction (Btg) can be expected to have a. a good soil structure and tillage b. a clay accumulation and grey colors c. a glazed appearance and transformations

b. a clay accumulation and grey colors

The three characteristics to look for in a wetland are: a. A long hydroperiod, hydrophobic plants, yellow colors in the profile b. a wetland hydrology, hydric soils, hydrophytic plants c. good soil structure, a lot of reds and yellows in the profile, a silt loam texture

b. a wetland hydrology, hydric soils, hydrophytic plants

Soil quality is a term used to describe the soils _________. a. the ability of the soil to purify water. b. the ability to carry out ecological functions c. amount of nutrients a soil can provide

b. ability to carry out ecological functions

Subsurface ditches are an effective way to remove large volumes of water a. after the soil has reached saturation b. after it enters the soil and filled the micropores c. before it enters the soil

b. after it enters the soil and filled the micropores

Humus is an important soil colloid. It is like 2:1 type minerals in which of the following characteristics? a. influence of isomorphic substitution b. capable of absorbing cation c. structural framework of the particles

b. capable of absorbing cation

Secondary minerals are most prominent in the ________ fraction of soils. a. sand b. clay c. organic d. silt

b. clay

Secondary minerals are most prominent in the ________ fraction of soils. a. sand b. clay c. silt

b. clay

Which of the following irrigation systems produces the most biomass per unit of water applied? a. furrow irrigation b. drip irrigation c. flood irrigation

b. drip irrigation

Some cations are important in remediating soil crusting problems because they ________. a. stabilize macro aggregates b. help to flocculate the soil colloids c. are active in the formation of soils crusts

b. help to flocculate the soil colloids

You find that the CEC of a soil at pH 5.0 is 16 cmolc/kg and at pH 8.2 it is 16 cmolc/kg. What is the most likely reason for this difference? a. ionization of carboxyl and phenolic groups to release H+ ion b. Isomorphic substitution creating permanent charge in the clay micelle c. increase the pH-dependent charges 2:1 type silicate clays

b. isomorphic substitution creating permanent charge in the clay micelle

What happens to pH dependent charge as the pH of the soil increases? a. it decreases b. it increases c. nothing

b. it increases

If you were seeking a soil colloid with a low capacity to absorb ions, but something that would provide a very stable base for a foundation, which of the following would you choose? a. vermiculite b. kaolinite c. montmorillonite

b. kaolinite

Additions to the soil primarily affect the soil profile through a. wind blown sand b. organic matter c. water movement

b. organic matter

A cool, wet climate is likely to produce soils high in ________, while a hot, wet climate is likely to produce soils high in ____________. a. horizonation, vegetation b. organic matter, iron and aluminum oxides c. sand, silt

b. organic matter, iron and aluminum oxides

Of the various types of drain systems, open ditch systems are most practical and economical for use on _____________. a. vertisols b. poorly drained soils with sandy profiles c. soils with a deep water table

b. poorly drained soils with sandy profiles

The transformation process changes a. the location of primary and secondary minerals in the soil profile b. primary minerals to secondary minerals and highly resistant end products c. fertile soils to infertile soils

b. primary minerals to secondary minerals and highly resistant end products

Some soil colloids exhibit positive charges under highly acid conditions. To what are these charges likely due? a. substitution of lower valent atoms for higher valent atoms in the octahedral sheet b. protonation of some hydroxy groups by excess H+ ions c. the release of some OH- ions leaving an unsatisfied positive charge on the colloid

b. protonation of some hydroxy groups by excess H+ ions

The map on a detailed soil map in a county soil survey report (same as Web Soil Survey) are most likely to be labeled with names from which category of Soil Taxonomy? a. subgroup b. series c. order

b. series

Which of the following is a characteristic of the clay fraction but not the sand or silt fractions of the soil? a. has medium to large pore space b. shaped like flakes or platelets c. has no chemical or physical properties

b. shaped like flakes or platelets

A soil with a smooth feeling likely has a high percentage of which soil separate? a. sand b. silt c. clay

b. silt

The amount of different sizes of mineral particles in a soil defines the soil ________. a. pore space b. texture c. structure

b. texture

The process of soil formation is a complex interaction of a. the five soil forming processes and four soil forming factors b. the four soil forming processes and five forming factors c. The illuviation of organic matter, clay, and iron and aluminum oxides

b. the four soil forming processes and five soil forming factors

The swelling/shrinking tendency of some silicate clay minerals is due primarily to _______. a. the presence of cations attracted by the negative charges on the internal surfaces b. the movement of water molecules in and out of the interlayers of the crystal c. expansion in the width of the interlayers due to movement of larger ions such as K+

b. the movement of water molecules in and out of the interlayers of the crystal

What is the bulk density of a soil with a wet weight of 57 g, a dry weight of 53 g and occupies 37 cm3? a. 2.65 g/cm3 b. 1.31 g/cm3 c. 1.43 g/cm3

c. 1.43 g/cm3

Given the information in the table, calculate the CEC of this soil 1 Kg of soil contains 8 cmolem as Ca2+ 3 cmolec as Mg2+ 2 cmolec as K+ 1 cmolec as Na+ 2 cmolec as Al3+ 1 cmolec as H+ a. 20.5 b. 12.5 c. 17

c. 17

In a soil with a bulk density of 2.2 Mg/m3, what is the % pore space (Assume Dp = 2.65 Mg/m3). a. 50% b. 35% c. 17%

c. 17%

In which of the following horizons has the process of illuviation most likely occurred? a. A horizon b. E horizon c. B horizon

c. B horizon

If you start with 40 g of soil, and the first hydrometer reading is 22 g/L while the second is 14 g/L, what is the soil texture? a. Loam b. Sandy loam c. Clay loam

c. Clay loam

Organic matter additions to a soil have no effect on: a. porosity b. Db c. Dp

c. Dp

The following are characteristics of a water molecule. a. It is attracted to surfaces with negative but not positive charges. b. The two H atoms are on diametrically opposite ends of the molecule c. It has a positive and a negative side.

c. It has a positive and a negative side

The hydrologic cycle is the cycling of water from the atmosphere to the ____________, and then from the soil to either surface water or groundwater, and then to the oceans and back to the atmosphere. a. Air b. Water c. Soil

c. Soil

Which of the following statements is correct? a. Limestone parent materials enhance the process of acidification. b. Highly weathered end products have been subject to weathering for short periods of time. c. Soils on hillsides tend to be shallower than those on level lands.

c. Soils on hillsides tend to be shallower than those on level lands.

Alluvial parent materials are those transported by a. Gravity b. Wind c. Water

c. Water

If you wanted to find a soil where physical weathering dominated over chemical breakdown you would be most apt to find it in: a. a coastal plain area of Delaware. b. a humid region in Brazil. c. a desert region of Arizona.

c. a desert region of Arizona.

A soil with an oxidation/reduction (redox) potential of 280 mV considered to be: a. well drained b. aerobic c. anaerobic

c. anaerobic

The presence of rocks such as shale and sandstone indicate the existence of ________. a. a high water table b. old mountain ranges c. ancient seas

c. ancient sees

Soil crusting is due to aggregate: a. formation b. flocculation c. dispersion

c. dispersion

A soil with a Bx horizon is likely to have a _________ indicating a potential perched water table. a. a subsoil with very low bulk density b. deleted B horizon c. fragipan

c. fragipan

Compared to silt, clay-sized soil particles are characterized by: a. Less tendency to form hard clods when dry. b. greater proportion of primary minerals. c. greater attraction for water.

c. greater attraction for water.

Which of the following practices is (are) useful in stabilizing surface soil structure? a. use of inorganic mulches b. all of the answers c. growing grass sod d. maximizing tillage

c. growing grass sod

The layers of contrasting material found when one digs a hole in the ground are called __________. a. pseudoliths b. pedons c. horizons

c. horizons

The reaction "mica + H2O -> K+ + OH- + 6HAlSi3O8 (acid clay)" is an example of __________. a. hydration b. oxidation c. hydrolysis

c. hydrolysis

Increasing the organic matter content of a soil is likely to: a. decrease the soil's water holding capacity. b. have no effect on water holding capacity. c. increase the soil's water holding capacity.

c. increase the soil's water holding capacity.

The element most often involved in oxidation reactions as minerals weather is _________. a. aluminum b. magnesium c. iron

c. iron

The matric potential of soil water ________. a. is lower in a sandy soil with 20 percent soil water than in a clay soil with same percentage of moisture b. is little affected by soil solids c. is not influenced appreciably by the force of gravity

c. is not influenced appreciably by the force of gravity

The negative charges associated with monmorillinite clay crystals are due mostly to _____________. a. isomorphic substitution of Al for Si in the tetrahedral sheet b. isomorphic substitution of Si for Al in the tetrahedral sheet c. isomorphic substitution of Mg for Al in the octahedral sheet

c. isomorphic substitution of Mg for Al in the octahedral sheet

The electronegative charge on 2:1 type silicate clays is due primarily to __________. a. extremely small size of the individual colloid particles b. the preponderance of tetrahedral sheets compared to octahedral sheets c. isomorphic substitution of one metallic atom for another in the crystal structure of the clay

c. isomorphic substitution of one metallic atom for another in the crystal structure of the clay

Subsurface land drainage is beneficial because ____________. a. it increases the availability of iron and manganese in acid soils b. it slows down the rate of soil warming in the spring c. it increases the depth of root penetration in the soil

c. it increases the depth of the root penetration in the soil

Given the family: fine-sandy, smectitic, mesic Aquic Haplaudalf, what do you know about this soil? a. it is dominated by kaolinitic clays b. it has a deep A horizon c. it is likely formed under a forest

c. it is likely formed under a forest

A soil with grey mottling occurring at 22" belongs to which drainage class? a. well drained b. poorly drained c. moderately well drain

c. moderately well drain

You are working with a soil colloid known to have a cation exchange capacity of about 100cmolc/kg of clay and a tendency to swell when wetted. Which of the following is it mist apt to be the dominant clay mineral in this soil? a. fine-grained mica b. kaolinite c. monmorillinite

c. monmorillinite

A subsoil that is identified as a Btg would have _________. a. an umbric horizon b. yellow colors c. mottles

c. mottles

Which of the following is not a textural class name? a. clay b. loam c. sandy silt

c. sandy silt

Soil texture describes the _____ of particles in a soil. a. arrangement b. colors c. sizes

c. sizes

A septic system needs soil to allow the waste water to move __________ enough to filter impurities. a. fast b. the waste water should not move at all. c. slowly

c. slowly

Which of the following best characterizes the permanent wilting point of a soil? a. water content of a soil with water potential of about -0.1 to about -0.3 bar b. maximum capacity of a soil to hold water c. soil with water potential of -15 bar

c. soil with water potential of -15 bar

Mechanical weathering processes result in: a. the hydrolysis of minerals through frost action. b. the decomposition of primary minerals. c. the disintegration of rocks due to differential expansion of minerals.

c. the disintegration of rocks due to differential expansion of minerals.

If you dug a deep hole in your backyard and water started to seep into the hole it would fill the hole up to ______________. a. field capacity b. the infiltration rate c. the water table

c. the water table

We must use our soils wisely and protect them because _________. a. they are a never ending source of clean water and plant nutrients b. they are easily formed and thus, a renewable resource c. they are a reusable, but not renewable, resource

c. they are a reusable, but not renewable resource

The four soil formation processes are: a. montmorillinosis, oxidation, illuviation, and mineralization b. weathering, oxidation, exfoliation, and acidification c. translocation, transformation, additions, and losses

c. translocation, transformation, additions, and losses

In which of the following situations would you expect downward movement of soil water through the profile to be most rapid? a. sandy loam in upper layers with a clay band underneath b. sandy loam in upper layers withe a layer of coarse gravel underneath c. uniformly textured sandy loam profile

c. uniformly textured sandy loam profile

A soil has a thin A horizon, a distinct B horizon, has reasonably stable soil structure, and was formed under forest vegetation. In which suborder is it most likely classes? a. udults b. udolls c. ustalfs

c. ustalfs

Which of the following is a characteristic of soil colloids? a. structure containing C, H, O b. low water holding capacity c. very small size

c. very small size

The B horizon can be high in a. Clay b. Aluminum oxides c. Iron oxides d. All of the above

d. All of the above

Organic matter accumulation is most pronounced in the ____________. a. B horizon b. E horizon c. C horizon d. O horizon

d. O horizon

An important part of the definition of soil is that it is ___________. a. unconsolidated material b. able to support plant growth c. on the surface of the earth d. all of the above

d. all of the above

Which of the following will decrease the evaporation (E) from the soil surface? a. the use of no-till culture b. plastic mulch c. adding straw mulch to the soil surface d. all of the above

d. all of the above

Which of the following is not considered one of the five major factors influencing soil formation? a. native parent materials b. climate c. living organisms d. valence state e. topography

d. valence state