How many people could you keep alive with one tree?

Why is the theory of evolution important? it disproves all other theories about how life began. it provides a topic for debate. it is a unifying concept in biology. it explains how life began. i know for sure, it is not "it is a unifying concept in biology."

Is becoming less expensive to screen blood samples for dna certain diseases have genetic basis what is possible ethical concern about the availability of inexpensive dna testing

Which describes a grizzly bear’s habitat?