Following an intense drought in 2000 to 2004, descendant populations of Brassica rapa flowered much earlier in the season than those from predrought populations. Researchers agreed that this could be a result of strong selection during these four years. For natural selection to act on flowering time in B. rapa, all of the following must be true, except.

the answer is a or when it says crossing over

i would have a lunch. it's one big package of food, making it one food. : p

in the year 2850, humans successfully colonized mars. the martian modules that were constructed could hold only a small population of people. it is now a century later, and the population on mars has grown to 600 people. of the current mars population, 45 people express the recessive phenotype for phenylketon- uria (pku) syndrome (pp genotype).

explanation: