A:In; offered
B:With; offered
C:In; was offered
D:With; was offered
植物开花,通过传粉和受精作用后,花结构中的____继续发育成为果实.向日葵的子粒常有空瘪的,玉米的果穗常有缺粒的,主要就是由于____不足引起的.