Many scientists believe that the surrender period of global warming is related to increased levels of?
a. radon being released from the earths surface
b. nitrogen in the earths atmosphere
c. carbon dioxide in the earths atmosphere
d. hydrogen in the outmost layer of the earths atmosphere

Which of these statements is true about autotrophs, but not heterotrophs? a. they use sugar and oxygen to make carbon dioxide and water.b. they use chlorophyll and oxygen to make carbon dioxide and water.c. they use sunlight, water, and carbon dioxide to make sugars.d. they use sunlight, water, and oxygen to make chlorophyll.