B. are more difficult to control than point sources. This is because A. is wrong (point source), and C. is wrong, because it doesn't necessarily cost less or more to identify the sources. D. may be right, as non point sources are natural, such as snow melts or rain.
The vegetation in most environments is crucial as a food source for many animals in the area. Without it, many animals may starve, thus setting on a chain reaction of animal displacement.
Well it's thought that the oxygenation of the atmosphere contributed to the evolution
Plant have both cell wall and cell membrane but animal have only cell membrane
There are four classes of macromolecules (polysaccharides or carbohydrates, triglycerides or lipids, polypeptides or proteins, and nucleic acids such as DNA & RNA). Carbohydrates and lipids are made of only carbon, hydrogen, and oxygen (CHO). Proteins are made of carbon, hydrogen, oxygen, and nitrogen (CHON). Hope this somewhat helps!
( I'll put the rest in below )
