The correct answer is B.
Channels and pumps are transmembrane proteins that create hydrophilic tunnels across the membrane. This allows molecules to be diffused through them. The channels and pumps are highly selective and only allow the diffusion of specific molecules. The channel's structure blocks the contact of the molecule with the head and tail of the phospholipids that form the membrane. As we said, the channels and pumps are proteins, so they are formed by amino acids. Therefore, the molecules passing through channels and pumps, only come in contact with the amino acids.
Each "human body cell" has 46 chromosomes. But human sex cells have 23 unpaired chromosomes in each cell. Sex cells are created by a special type of cell division, Meiosis.
2 weeks at the most I know I've bought shirts from them before
Orientation behaviors usually determine the type of environment that an animal will prefer to live. Animal orientation behavior is a complex process which determine how an animal receives information from the external world and how it responds to it.
