Radiation, hydrogen, and helium
Answer:
One that has a dominant allele and a recessive allele.
1. Lung capacity is basically how much air (in volumes) your lungs can hold.
2. I think that a swimmer would be able to have the biggest lung capacity because when swimming, you are mostly underwater with no air, so being able to hold as much air in as you can when you come up to take a breathe will help improve how well you do.
