The formation of a geographic barrier such as a river causes fragmentation in a population. Gradually, genetic drift and natural selection cause genetic differences to accumulate. During a drought year the river dries up and the two populations begin to occupy the dry riverbed. The two populations do not produce viable offspring. Why?

The special sites along the chromosome where DNA replication begins are called ______.

Genetic fingerprinting, the unique banding pattern of an individual, is possible because

In the algebraic expression p2 + 2pq + q2 = 1, the q2 refers to:

Genes can be transcribed and translated even after being transplanted from one species to another. What basic fact makes this possible?

Modern biologists have concluded that the beak shapes of the finches Darwin collected while on the Galapagos Islands are 

True or false? All ribosomes begin translation as free ribosomes. As protein synthesis begins, the protein itself will cue the ribosome to attach to the ER if necessary.

In the second level of DNA organization, the string of nucleosome beads coils to form the thick ______.

True or false? Most DNA mutations have either a neutral or negative effect on the resulting RNA or protein product.

Which of these is NOT a way in which viruses evolve?