Most of the oxygen we breathe is a result of ?

We want most cells to be even in and out which is called

What is true of sea slugs in these orders

The greenhouse effect a. something that has occurred for millions of years b. an unnatural phenomenon caused by humans that maintains earths temperature range. c. the results of the differences in the angle of the suns rays d. an unnatural phenomenon that causes heat energy to be radiated back into the atmosphere