Crawford's teacher tells him that all objects exert gravitational forces on one another and these forces depend on the distance between the two objects. Crawford wants to know why, if this is true, he cannot slide the books on his desk toward himself without reaching out and touching them, but the Earth can move objects without making contact in this way. Which statement offers the best explanation for Crawford's question?

answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms

answer: grassland biomes are closer to the equator and receive more rain.

grasslands are biomes that are dominated by grasses rather shrubs and trees. savanna are biomes that exhibit grasses, shrubs and small tree as vegetation. grasslands are located near the equator of the earth. these are found in north america. savanna biomes are found in africa, south america, australia and india. grassland exhibit moderate climatic conditions, it receives   amount of rainfall higher than savanna.   therefore, savanna exhibit dry and hot climatic conditions.