Your answer is actually all correct. Great job! A heterozygous combination would just implicate greater power to the 'dominant' dominant allele.
Introns because they are coding sequences.
Exons because they are non-coding sequences.
B- Reproducing more often. If the environment is not right for them then reproduction doesn’t help them adapt. They respond by changing behavior, moving to another area, and even modifying their physical bodies (diets included).
