Which is not a cause of evolutionary changes in organisms ?
1. environment 2. biologist 3. dna 4. cells

Here's one way to follow the scientific method. place the missing steps in the correct position in the process.

Prior to the development of dna fingerprinting, blood type could be used to determine possible parentage. although it might prove someone was not a parent, it could not show if someone was positively the parent, only that he or she might be a parent. which of the following is a true statement that can be made about parentage based on blood typing?

Ascientific idea becomes valid when it is what?