what basic concept of biology includes the idea that new cells can be produced only by the division of existing cells

In natural selection, what is actually “selected? ” a) alleles are directly selected b) genotypes are directly selected c) phenotypes are directly selected d) entire populations are directly selected

How does the molecular clock work? a. it analyzes the brain functionality of two different species.b. it examines and compares the physical characteristics of two different species.c. it illustrates relationships between two different species.d. it compares the number of mutations that exist in the dna of two different species.

Which of the following is the earliest era of earth's geologic time scale? cenozoic mesozoic precambrian paleozoic