Broccoli, cabbages, and brussels sprouts all descend from the same wild mustard and can still interbreed. These varieties were produced by

Answer: Artificial selection

Explanation:

Artificial selection is the process of intentional breeding of plants or animals by selecting the parents with good features so as to produce new plants that have the qualities of both parents.

Wild cabbage was the uncultivated form of Brassica oleracea. It was chosen a parent plant for growing broccoli, brussel sprouts and cabbage by artificial selection. The variety was chosen to produce plants with large flower buds, edible stems and large leaves through artificial selection.