Semi permeable means that some things can go in and out of the cell, but some cannot. Permeable means it allows things to pass through it, so semi permeable means only some things pass through.
Answer:
Iron, Magnesium, and Nitrogen
When animals are fighting over resources the number of one animal might decrease because the other animal would've tried to kill it and stay alive
when there is competition the population size of one animal might decrease while another increases<span />
How it was formed is the answer
By moving substances across membranes, transport proteins make everything from nerve impulses to cellular metabolism possible. Without transport proteins, for example, the sodium-potassium gradient that allows our nerves to fire would not exist.
