A meteroite is a meteor that struck earth
a meteorode is a small rock in space that could eventually turn into a meteor
asteroids are a cluster of meteors
comets are icy meteors, seeing that the oort cloud is mostly ice i would say that the answer is comets.
The answer is most likely testing. scientists test their data againt their hyputhesis.
After completing the punnett square, you end up with 50% chance for curly hair and 50% for straight hair. Hope this helps :)