Answer: I believe it is A. DNA polymerase checking the DNA
The dependent variable would be the heart rates of her classmates.
The question is about a test cross. Definition of a test cross: Generally a cross involving a homozygous recessive individual. When a single trait is being studies, a test cross is a cross between an individual with the dominant phenotype but of unknown genotype (homozygous or heterozygous) with a homozygous recessive individual. If the unknown is heterozygous, then approximately 50% of the offspring should display the recessive phenotype. If the individual is homozygous all the progeny will have the dominant phenotype. James' suggestion to use show the result of the two possible crosses with a Punnet square is a great suggestion.
Answer:
The Testes.
Explanation:
Testes are contained in a sac of skin called the scrotum, it produces sperm, then make hormone testosterone. It aids testosterone which promotes the development of secondary sexual characteristics, which in humans include a deeper voice, more body hair, and more powerful muscles than that in their counterparts which are the female.