Answer:
Sometimes, molecules cannot move through the cell membrane on their own. These molecules need special transport proteins to help them move across the membrane, a process known as facilitative diffusion. ... Many channel proteins allow the diffusion of ions. Ions are charged atoms.
Explanation:
Cells<span> are </span>small<span> because the ratio of surface area to volume is the most efficient at their size. This is because when you have a lot of </span>small<span> objects </span>vs<span> a few </span>big<span> objects the surface area is much </span>larger<span> in relation to volume.</span>
Heredity or something like that I don’t speak English sorry
These bones are expanded into broad, flat plates, as in the cranium (skull), the ilium (pelvis), sternum and the rib cage. The flat bones are: the occipital, parietal, frontal, nasal, lacrimal, vomer, hip bone (coxal bone), sternum, ribs, and scapulae. ... In an adult, most red blood cells are formed in flat bones.
As viruses cannot reproduce by themselves, they depend on the host cells that they infect to reproduce
