29. A common feature of thermal pollution and artificial eutrophication is that they both
a. have sources that are difficult to identify and control
b. cause large mats of algae to bloom in fresh water
c. are a result of power plants and other industrial activity
d. decrease the amount of oxygen dissolved in water
D?
33. A true statement about the greenhouse gases is that they
a. convert sunlight into heat energy that warms Earth
b. are concentrated in the stratosphere
c. trap heat that is radiated upward from Earth
d. are not affected by human activity
I'm confused beween A and C
42. The critical difference between today's global warming and Earth's previous climate changes is that
a. human-made chemicals such as CFSs do not influence global warming
b. previous changes in climate were dramatic but very short-lived
c. scientist can now save all species from extinction by genetic engineering
d. global warming may occur much more rapidly than it did during previous climate changes due to rising carbon dioxide levels
I think it's D
2 answers