Cells with similar structures and functions work together to form
a. organisms.
b. organs.
c. tissues.
d. systems

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

increases the risk of extinction 

explanation:

the answer is that if the species suffers from the disease, there is nothing stronger than the others, so it is possible to remove wholeness. an example of this is hunger in irish potatoes, which has a deadly disease bearish part of all potato harvest masses. pretty much ruins the land of crops.