B-valine,histidine,threonine,phenylalanine
Answer:
I feel like B is the correct answer
Explanation:
B is correct
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.
Answer:
Higher oxygen levels means animals can grow larger and still maintain the supply of oxygen to their muscles. Falkowski and colleagues calculated fluctuations in the atmosphere's oxygen levels from cores of deep-sea rocks dating back 205 million years.
