Question

in the body, why do muscle cells and skin cells look and behave differently?
there is no similarity in their chromosomes.
they have different genes.
their genes are being expressed differently.
the same genes are being expressed in both types of cells

Explanation:

1. Analyze the first option: Muscle and skin cells are from the same organism, so their chromosomes are similar (same set in most cases), so this option is wrong.
2. Analyze the second option: Muscle and skin cells have the same genes (since they are from the same organism and share the same genome), so this option is wrong.
3. Analyze the third option: Cell differentiation (like muscle vs skin cells) occurs because different genes are expressed (or same genes expressed differently) to give cells different functions and appearances. This matches the concept of gene expression regulation in cell specialization.
4. Analyze the fourth option: If same genes were expressed, cells would be identical, but muscle and skin cells are different, so this option is wrong.

Answer:

C. Their genes are being expressed differently.