What is the original source of variation that natural selection can act upon?

Q: a pair of homologous chromosomesa) always has the same genes and the same allows b)always has the same genes c)always has the same alleles d)never has the same genes

How does a lytic infection differ from a lysogenic infection?

Plz ! cattle ranchers and dairy farmers rarely allow all of their animals to reproduce instead they practice selective breeding and only encourage the reproduction of animals with specific features. which of the following cows would a dairy farm most likely choose to reproduce? a. a cow that makes a lot of milk. b. a cow that can run quickly. c. a cow with a think, soft fur. d. a cow with large, strong hooves.