Answer:
Cells are the basic building blocks of all living things. The human body is composed of trillions of cells. They provide structure for the body, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions.
It's B, Bowman's capsule !
If one population, such as lets say a hawk decreases the niche, or the importance of an animal or its effect in the ecosystem, on the mice. the mice population increases. or it can be lets say plants and bugs, the lady bug goes away and the other bugs eat the plant