Which of the following are true?

a. primary succession begins in an area that does not have soil.

b. secondary succession occurs in an area that already had life and soil.

c. primary succession begins in an area that did not have life before.

d. all of these are true.

14) whenever diploid populations are in hardy-weinberg equilibrium at a particular locus a) the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change. b) natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency. c) this means that, at this locus, two alleles are present in equal proportions. d) the population itself is not evolving, but individuals within the population may be evolving.