单项选择题
A．jump as high as you can B．slide down a rope to the ground C．attach yourself to a rope and fall to the ground D．fall towards the ground without a rope
A．One kind of animals is eaten up. B．One kind of plants is destroyed. C．One kind of animals eats another. D．One of the links is destroyed.
A．from water B．from the air in the sky C．from the soil D．from water, things in the soil and air and sunlight