I think it is natural selection. genetic variation also could be a factor for physical variation over the years.
Hamburger becuase you cook it on a grill and then you put it in a bun. You can add pickels, cheese, mayo, ketchup, and pretty much anything to it.
i hope im right
<span>What type of milk and milk products should be included in a healthy diet?
c. fat-free or low-fat
</span>
Passive and intovert types of humans often like to be more alone and deal with one or fewer people in general as opposed to being and talking all around to every possible person they could find at a party or a bar, or just any place in general.
