That answer would be A. nucleus
Answer:
Explanation: Trophic level, also called feeding level, is defined as the feeding level or each stage in a food chain or food web. In other words, trophic level is the number of links by which food energy is transferred from producers to final consumers. For example, in a food chain like the one below, we can have these levels.
By controlling what enters and leaves a cell, the cell membrane A) aids in maintaining homeostasis within the cell. Homeostasis is the process by which organisms maintain life through eating, growing, and living in variable conditions. It would not make sense to answer B) because organisms do not control the homeostasis of their external environment. D) also would not be correct because cell's do not control osmosis in the external environment. The membrane does not control osmosis because osmosis is generally a random process of molecular diffusion whereas the membrane acts in a conscious and controlled way.