What does an earth scientist study?

a animal cells

b machines

c oceans

d farming methods

Option C, Ocean

Explanation:

An earth scientist study about the earth, its origin , its structure and components such as mountains, rivers, ocean, plateau & other geographical and topographical feature.  

An earth scientist is not at all concerned with the study of animal cells, machine and farming methods. The studies related to an animal cell is carried by a biologist, studies related to machines is carried by mechanic /engineer and studies related to farming methods is carried by agriculturalist.  

Hence, option C, oceans is correct.

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.