the answer is a <u><em>phospholipid bilayer</em></u>
it's called phospholipid because it's made of a group of lipids that has a phosphate group and bilayer because it's made of hydrophilic heads that are exposed to the solution and hydrophobic tails that are directed inwards
Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, isolation and habitat area.
It would 7 billion years which is B.