Some people have nearsightedness (myopia) and farsightedness (hyperopia) because the distance between their and their is either too short

lens; retina

In myopia, close objects look clear but distant objects appear blurred. Hyperopia is the reverse of myopia. Here you can see distant objects clearly, but have difficulty focusing on objects that are near. People have myopia (nearsightedness) and hyperopia )farsightedness) because the distance between their lens and their retina is either too short or too long.

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all these collisions do one thing, and that thing is explained in the last option. when dusst, rocks and ice collide, they harden and form giant layers of rocks or hard ice.

d)   to harden materials to form different parts of earth’s layers

hope it ,

bioteacher101