I think the answer is b, because cartilage is what helps with flexibility in tissues....
Food web stability is most dependent on the number of connections among species.
Answer:
Human skin pigmentation is the product of two clines produced by natural selection ... The populations exhibiting maximally depigmented skin are those ... &c., are of the nature which it might have been expected would have been ... The evolution of light pigmentation at high latitudes has long been related ...
Explanation:
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.
