Gene flow is partially responsible for .. a) genetic sameness b) genetic variation

The gene flow is responsible for the (b) genetic variation.

The gene flow is a concept of genetics where the genes or alleles move between the individuals in an interbreeding population of species. When a member belonging to a particular gene pool (collection of unique genes) mates with another member of a different gene pool, the gene frequencies change for the various genes in the progeny. This helps in maintaining the genetic variation in the population of the interbreeding species.

equal distribution i think.

the alkaline earth metals (beryllium (be), magnesium (mg), calcium (ca), strontium (sr), barium (ba), and radium (ra)) are a group of chemical elements in the s-block of the periodic table with very similar properties: shiny. silvery-white. hopefully this ? i didn't fully understand the question