Agriculturists have developed some varieties of vegetables from common wild mustard plants, which reproduce sexually. which statement best explains the development of these different varieties of vegetables?
a. different species can develop from a single species as a result of the effect of similar environmental conditions.
b. different varieties can develop from a single species as a result of the recombination of genetic information.
c. variations in a species will increase when the tate of mitosis is decreased.
d. mutations will occur in the genes of a species only if the environment changes.

The answer is b. Different varieties can develop from a single species as a result of the recombination of genetic information. 

Varieties are a taxonomic level below subspecies, which is below species. They develop from a single species as a result of the recombination of genetic information. For example, Brassica oleracea is wild cabbage. From wild cabbage developed some varieties, in binomial nomenclature marked with var: Brassica oleracea var. oleracea - cabbage, Brassica oleracea var. italica - broccoli, Brassica oleracea var. botrytis - cauliflower.
They are all very similar because they are developed as the result of genetic recombination.

Plants, sunlight, growth and artificial sunlight

Sorry its not enough info