The bird is eating food caught between the alligators teeth?

Yes

Explanation:

Because some alligators sometimes let birds co-exist with them instead of eating them or attacking them.

the denominator has a very specific role.

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.