---Posted by Ash - Youtube.com/BlastedRoof / Youtube.com/BlastedAsh

1.
The question presupposes that there is an a priori reason for them to be anaerobic. There is no such reason. Nobody decided to make them anaerobic. The better question concerns the metabolic pathways by which the archaea live.
2.
They can survive in areas of the earth where no other life forms can be found. Ex. some of them can't survive in oxygen, and others are found deep inside the ocean vents.

3. 	i. Cell membrane of archaea have a different structure and chemical composition            than those of bacteria

	ii. Live without oxygen
4. A C