On average, how long does a persistent cough last after one recovers from pertussis?

Ineed to know why d is the correct answer asap

What would happen if the tubing with the yellow band was placed in a beaker of distilled water?

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.