Question

siamese cats have dark fur on their extremities (paws, nose, ears, and the tail), while the rest of their bodies are covered with lighter hair, despite the fact that only one gene controls their coat color. why does the coat color differ at different places on a siamese cat’s body?

melanin can be produced in the extremities because they are colder than the rest of the body.

tyrosinase, which is needed for pigment formation, does not function in the colder extremities.

tyrosinase, which is needed for pigment formation, does not function in the warmer extremities.

melanin can be produced in the extremities because they are warmer than the rest of the body.

Explanation:

To solve this, we analyze each option:

• Option 1: Siamese cats' extremities (paws, nose, etc.) are colder. The gene - controlled tyrosinase (for pigment) is temperature - sensitive. In colder extremities, tyrosinase functions, allowing melanin (dark pigment) production. So melanin can be produced here as they are colder, making this option correct.
• Option 2: If tyrosinase didn't function in colder extremities, melanin (pigment) wouldn't be made there, and extremities wouldn't be dark. So this is wrong.
• Option 3: Extremities are colder, not warmer. So this is incorrect.
• Option 4: Extremities are colder, not warmer, so this is wrong.

Answer:

A. Melanin can be produced in the extremities because they are colder than the rest of the body.