<span>A.
to fuel their chemical reactions</span>
Answer: Because it is harder to draw breath in. And the cold
Explanation: At higher altitudes, it becomes more dangerous, and you can develop altitude-related illnesses such as HAPE and HACE. I read a book called<em> Into Thin Air</em>, and in the book the author goes into detail on the details/complications of climbing Mt.Everest and oxygen needs. Mountain climbers use canisters of oxygen called <u>Supplemental Oxygen.</u>
its obviously not child labor or economy based because those have nothing to do with the environment so its the other three.
Answer:
A forest ecosystem can support a limited number of bears because bears are the supreme predators of their ecosystem and very few animals can hunt bears so nature by supporting a limited number of bear populations supports a balanced number of population of its prey like insects, fishes, deer.
Another reason for the limited population of bear is that bear occupies the highest trophic level in the ecosystem so according to 10% law of energy transfer, it will get very less energy from its food so it needs to eat more.
Therefore the population of bears is limited because the environment can not meet the energy requirement of many bears so a forest ecosystem can support a limited number of bears.
Answer:
The correct answer is "Red shift"
Explanation:
Blue shift: When the source and observer approach one another, the evident frequency increments or apparent wavelength diminishes. Here the Doppler shift is positive. This is known as blue shift.
Red shift: When the source and observer move away from one another, the clear frequency diminishes or apparent wavelength increments. Here the Doppler shift is negative. This is known as red shift.
