How large should established protected areas be?

Delegates at the 1992 Fourth World Congress on National Parks and Protected Areas, a decennial international conference that serves as a global forum for setting the agenda for protected areas worldwide, recommended that “protected areas cover at least 10 percent of each biome by the year 2000.”

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

the answer is :