下列关于生物个体发育的叙述,哪些是家蚕和青蛙都具备的特点( )
①发育过程在水中进行 ②发育的起点是受精卵 ③发育过程有蛹期 ④幼体和成体有很大差异.
A:①④
B:②③
C:①③
D:②④
up in to on from
It's fine today. Let's _______ out to play.