A.莲既可进行有性生殖又可进行无性生殖 |
B.青蛙一次可产卵数千枚,是对其卵受精率低和受精卵发育率低的一种适应,有利于青蛙的繁衍。 |
C.鹌鹑卵的卵黄表面中央有一盘状小白点,称为胚盘,里面含有细胞核 |
D.蝗虫的发育经历了卵―幼虫—蛹—成虫四个时期 |

同类型试题

y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2


y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2

