21. Choose one of the hypotheses from Question 20. Describe how you could set up an experiment to test the hypothesis by listing your experimental groups, control group, and at least 2 constants you would need to have.

the correct answer is:

a population changes in response to a change in the environment.

idk lol use google m8

the tricuspid valve is present between right atrium and right ventricle

the correct answer is: b. pantala flavescens, because these organisms would have a high level of genetic variation due to sexual reproduction.  

because involves two organisms (parents) whose genetic material combines, sexual reproduction leads to genetic variation in new generations of offspring. the offspring is an unique organism, with new genome, more protected with the higher ability to adapted. this process is fundamental to evolution.