Answer:
Much change is due to random genetic drift rather than positive selection. Some are harmful and are likely to be eliminated by natural selection – by death of the embryo, for instance. ...
a chemical element or substance required in trace amounts for the normal growth and development of living organisms.
Answer: They usually run tests too see. For example, that's why they made blood tests. They take you blood from you, and run tests to see if you have a disease.
Explanation: Hope it helps!
I don’t really understand this question can you go more into detail
