Answer:
<h2>Blood flow through a capillary is controlled by the <u>precapillary</u><u> </u><u>sphincters</u><u>.</u></h2>
If those are the only answers i would say mutualism
The Election Transport Chain
The generalization that all organisms are composed of cells was established through multiple observations in various kinds of animals and plants. A controlled experiment of finding cells in all the kinds of living organisms is not possible or is infeasible as it will require prior knowledge of all the kinds of organisms inhabiting Earth and the effort to catch and bring them in the controlled environment of the lab for testing.