Answer:
oxygen because
Explanation:
because u can survive 3 days with out it and if u did not have oxygen u would suffocate
Answer:
I'm pretty sure it's transport blood cells
D colors of UV rays separate base on on their wavelength
In an atom, the number of protons is almost always equal to the number of electrons
Answer:
Channel protein.
Explanation:
Channel protein have gate that opens and close which allow the passage of polar substance or ions to move to permeable membrane of the cell by diffusion. They are water filled and allow the movementof charged molecules inside and outside the cell membrane i.e polar molecules move through non polar bilayer of the cell membrane.