Why do phospholipids tend to spontaneously orient themselves into something resembling a membrane?

Which of the following will not cause mass extinction? a. drastic change is weather b. geological change c. both a and b d. none of the above

Which of the following are false concerning microbes? a. microbes generate oxygen through photosynthesis. b. the primary role of microbes on the planet involves causing disease in animals and humans. c. microbes produce vitamins in the intestines. d. microbes play a role in breaking down waste and decomposing dead organisms.

In what for do plants utilize nitrogen? why do they need nitrogen?