How can two individuals compete without ever coming in contact with each other

Robert wants to know which fertilizer will work the best for his grass. what can he do to explore this inquiry?

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?

Sea stars, sea urchins, sand dollars, and brittle stars are all memeber of a group, what is the common name of the group they are all in