Presidential power enumerated in the US Constitution for the President are Commander in Chief of the Armed Forces, and Chief Executive. The answer is D.
European immigrants migrated
Trilobites were rapidly evolving and widespread marine organisms that spanned a number of geologic time periods. Certain types of trilobites only appeared in specific segments of geologic time; therefore, when one of these trilobites is found, you can be certain that the rock layer it is found in is of a certain geologic age.
More cars, more affucient society.