What is the main factor that prevents the growth of tropical plants in the norther part of the united states?

An atom of nitrogen had seven protons in its nucleus. how many electrons does it have

Atypical human cell is approximately 12.00 μm in diameter and enclosed by a membrane that is 5.000 nm thick. (a) what is the volume of the cell including the membrane? (b) what is the volume of the cell membrane? (c) what percent of the total volume does its membrane occupy? to simplify the calculations, model the cell as a sphere. enter your answers using four significant figures.

According to the cladogram, which organisms have roundworms as a common ancestor?