試題詳解

7. In angosperm, what does double fertilization mean?
(A) One sperm is needed to fertilize the egg, and a second sperm fuses with the two nuclei in the large central cell of the female gametophyte.
(B) Every egg must receive two sperm to produce an embryo.
(C) Flowers must be pollinated twice to yield fruits and seeds.
(D) The pollen grain must germinate twice to produce a pollen tube.
(E) Fertilization must occur both in the spring and in the fall.