e.s 3.2
Many people consider ozone proaction an international environmental success story. Scientists continue working to protect the ozone layer because CFC molecules remain active in the stratosphere for ___ years
60-120
are clouds that form at altitudes of about 21,000 m during the arctic and antarctic winter or early spiring, when air temperatures drop below -80ºC
Polar stratospheric clouds
The destruction of ozone causes a thin spot, or ____, which lasts for several months
ozone hole
UV light can damage plants by interfering with ___
photosynthesis
High levels of UV light can kill _____ that live near the surface of the ocean
phytoplankton
strong circulating winds over Antartica, called the _____, isolate cold air from surrounding warmer air
polar vertex
At the earth's surface, CFCs are chemically ___. They do not combine with other chemicals or break down into other substances.
stable
But CFC molecules break apart high in the ____ where UV radiation is absorbed
stratosphere
By shielding earth's surface from most of the sun's UV light, the ozone in the stratosphere acts like a ____ for earth's people
sunscreen
is a thinning of stratospheric ozone that occurs over the pole during the spring
the ozone hole
is the layer of the atmosphere at an altitude of 15 to 40km in which ozone absorbs ultraviolet solar radiation. Ozone is a molecule made of three oxygen atoms.
the ozone layer
When sunlight returns to the South Pole in the spring, molecular chlorine is split into___ chlorine atoms by UV radiation. The chlorine atoms rapidly destroy the ___.
two;ozone
are hydrocarbons in which some or all of the hydrogen atoms are replaced by chlorine and fluorine -they destroy ozone molecules
Chlorofluorocarbons
a group of nations made an agreement, called the _____, to sharply limit their production of CFS
Montreal Protocol
____ is harmful to organisms because it can damage the ____ material in living cells
UV light;genetic
UV light is_____ to living things because it damages ____, the genetic material that contains the information that determines inherited characteristics
dangerous;DNA
As the amount of ozone in the stratosphere ____, more UV light is able to pass through the atmosphere and reach Earth's surface
decreases