Q1. In the 5-7 million years that hominid lineage has been diverging from its common ancestor with the great apes, dozens of hominid species have arisen, frequently with several species coexisting in time and space. As in recent times as 30,000 years ago, Homo sapiens coexisted with Homo neanderthalensis. Both species had large brains and advanced intellects. The fact that these traits were common to both species is most easily explained by which of the next?

a. species selection
b. uniformitarianism
c. sexual selection
d. species selection & uniformitarianism
e. species selection, uniformitarianism, & sexual selection

Q2. How might you deterine whether the turbidity in your nutrient broth tube was from a mixture of different microbes or from the growth of only one kind of microbe?