Which is not a hypothesis stated in the text for why the Cambrian explosion occurred? A. The different chemistry in the ocean made it easier for animals to secrete hard shells
B. A super volcano exploded changing the environment and causing change in the animals
C. Oxygen levels reached a level that allowed animals to be more efficient at using aerobic metabolism
D. The emergence of predatory animals that could move around and eat other animals favored animals that could move or protect themselves.

your answer is rna to the question.

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.