Answer:
1. are heterozygous for the disease.
Explanation:
<em>Since the disease causes the death of chicks before hatching, it means that those with the disease cannot be found in the population. In order for the allele of the disease to be passed from generation to generation, there must be parent birds that are carrying the disease in heterozygous state.</em>
Option 1 is the correct option.
A chemical reaction happens
Answer:
for question 1: an organism's behavioral change in response to a change in its environment
for question 2: a mole has a sensitive sense of smell to help it find food underground
for question 3: natural selection
