1the atmosphere<span> also protects living </span>things<span> on Earth from the sun's harmful ultraviolet radiation. 2</span>tmosphere filters out these dangerous rays. 3The atmosphere<span> also helps to sustain life of Earth. .4blocks harmful electromagnetic 5.provide oxgen</span>
Because if something goes wrong there can be mutations and cause the rest to the replication to mutate I believe
Hair shaft is the one that you will see on the body surface.
Number 2 because they are still developing
