<span>Ocean currents bring nutrient-rich water into coastal regions.</span>
The correct answer is pretest and posttest .
A pretest/posttest experiment is an experiment that includes double measurements at multiple points in time. In this kind of test, measurements (measurement of dependent variable) are taken both before and after a treatment.
Answer:
A) The role of bacteria fixing nitrogen is very important because it fixes atmospheric nitrogen in the roots of plants. For example, Azotobacter is a bacteria which lives in the root of the higher plants. The bacteria fixes nitrogen for the plant and the plant gives habitat and food to the bacteria and hence, both get benefit.
B) Nitrifying bacteria are the bacteria which converts ammonia into nitrates. Examples are Nitrosomonas and Nitrobacter.
C) Denitrifying bacteria is a type of bacteria which converts nitrates into atmospheric nitrogen. Examples are Serratia and Pseudomonas.
This is a difficult answer because the way you worded it but I believe I understand. The answer is chloroplast. They absorb light to help feed a plant cell.