I've checked all the options and I think that the right answer looks like this: Mollusks have highly developed olfactory receptors.
The immune system helps fight off infections and foreign invaders
Answer:
Mutations increase genetic variation and the potential for individuals to differ
Explanation:
Mutations can result in an organism having a new allele. When that organism produces offspring their offspring are most likely to inherit the allele created from the mutation which could potentially lead to genetic variation.
Echinoderms have radial symmetry.