Question

during artificial selection which features of wild cabbage were selected to give rise to cabbage and cauliflower

Answer 1

for very short distances between leaves cabbage have been bred and for sterile flowers cauliflower had been bred

Answer 2

Brassica oleracea is the scientific name of 'wild cabbage'. By artificial selection many other species like Brussels sprout, Kohlrabi, Kale, Broccoli, Cabbage, Cauliflower have been produced form this.

As per your question

1) In case of cabbage the selected feature is 'terminal buds'.

2) In case of cauliflower the selected feature is 'flower clusters'.