3. Speciation occurs when: * 1. two populations become geographically isolated
2.enough differences accumulate between two populations that they can no longer
interbreed
3.gene mutations accumulate
4.all of the above

your spelling is a little off : ]

the correct answer is option d.

an appositive is a noun, noun phrase or noun clause which follows another noun or noun phrase in order to describe it or name it another way. they are usually used between commas, brackets or dashes.

the example sentence with the correct use of commas is the following:

her uncle, the man over there in the red shirt, owns the hardware store in town.