20. Why viviparous animals have good advantage that oviparous animals?
A. because the can produce attractive offspring
B. because viviparous animals are caring animals.
C. because viviparous animals can concentrate on taking care of only new young
D. beacuse they are beautiful

21. A mature cell divides into two and so on the new cell grows in size and
the mature
A.placental
B.frogmentantion
C.oviparous
D.fission​