海葵、海蜇两种动物不具备的特征是( )
A:有口无肛门
B:结构简单
C:石灰质的骨骼
D:生活在水中
Any man eyes his head can see that he’s exactly like a rope.
切开苹果、梨等水果时会流出一些汁液,这些汁液主要来自( )