Which is a good example of genetic variation that could lead to adaptive evolution?
Riya and Melissa are identical twins who share similar interests and earn similar grades in school, but plan to attend different colleges.
Since moving to Arizona from Washington state, Bob's skin has become noticeably darker. Most days in Arizona are sunny; most days in Washington state are not sunny.
On an island where the trees bear only hard-shelled nuts, birds that have big, sharp beaks have a better survival rate than those with smaller beaks.
