A.扇贝具有两片坚硬的贝壳,能保护内部柔软的身体 |
B.爬行动物体表覆盖角质的鳞片或甲,可以保护身体,减少水分散失 |
C.鲫鱼的鳃丝中密布毛细血管,适于在水中呼吸 |
D.鸟的胸肌两端都附着在同一块骨上,有利于牵动两翼完成飞行动作 |

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

