Near Earth’s surface, occupies about 78% and about 21% of the total volume of dry air. a. hydrogen; oxygen b. nitrogen; oxygen c. oxygen; hydrogen d. nitrogen; water vapor

b.  Nitrogen; Oxygen

Explanation:

The air is a mixture of gases in the following percentage;

Nitrogen; 78%

Oxygen : 21%

Carbon(IV)Oxide : 0.03%

Argon : 0.9%

Others ( minute traces of Neon, Helium, Methane e.t.c) : 0.17%

as the gila monster consumes the eggs or young of the desert cottontail and gambel's quail, thus its main food supply is only accessible for a restricted time duration every year. however, for this, the gila monsters exhibit three adaptations, which elevate their survival rate in the desert condition.  

first, is that they possess huge bodies, and can consume greater concentrations of food during a small period. secondly, they require to feed infrequently as they can accumulate fat in their tails. ultimately, their rate of metabolism is very low, so that they can burn their reservoirs of fat gradually.  

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