Which factors are common to both gradualism and punctuated equilibrium?
a. migration, genetic drift, speciation, and natural selection
b. allele change and microevolution
c. slow adaptation, stasis, and expansion

A. Migration, genetic drift, speciation and natural selection.

Explanation:

Migration, genetic drift, speciation and natural selection factors are common to both .Gradualism and punctuated equilibrium are two ways of the evolution. Gradualism is  selection and variation that happens. Small variations are fit an organism. In punctuated equilibrium, change comes in spurts. There is a period of very little change, and only few huge changes occur, often through mutations in the genes of a few individuals. Mutations are random changes in the DNA. That are not inherited from the previous generation, but passed in next generation. Though mutations are often harmful, the mutations that result in punctuated equilibrium are very helpful to the individuals in their environments.