生态系统中生物种类和数量(单位:个)
| 物种1 | 物种2 | 物种3 | 物种4 | 物种5 | 物种6 | 物种7 |
① | 0 | 90 | 0 | 0 | 30 | 30 | 40 |
② | 200 | 350 | 0 | 0 | 30 | 0 | 40 |
③ | 150 | 250 | 100 | 800 | 40 | 30 | 1 |
④ | 300 | 200 | 0 | 0 | 0 | 0 | 50 |
A. ① B. ② C. ③ D. ④
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