Whales are mammals that live in the ocean and swim like fish. which characteristic in whales prevents them from being classified as fish?
a. they eat fish.
b. they produce milk for their young.
c. they bear live offspring
d. they reproduce sexually.

You have just sequenced a new protein found in mice and observe that sulfur-containing cysteine residues occur at regular intervals. what is the significance of this finding? it will be important to include cysteine in the diet of the mice. cysteine residues are required for the formation of α helices and β pleated sheets. cysteine residues are involved in disulfide bridges that form tertiary structure. cysteine causes bends, or angles, to occur in the tertiary structure of proteins.