List the four eras on the geologic time scale describe one identifying type of organism from each era

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?

The negative impacts of nonnative species generally outweigh the positive impacts

In the practice of science, this type of reasoning is used to develop explanations.