instruction:
Combine the given two facts to write a concluding fact. Note that there should be some parts of the first and second facts that are not mentioned in this conclusion fact. Your combined fact should be the result of a chain between the two facts. Chains form when two facts connect together to produce a concluding fact. An example of a chain is: "pesticides cause pollution" (fact1) + "pollution can harm animals" (fact2) → "pesticides can harm animals" (conclusion fact). Parts of the concluding fact overlap with the first and the second fact. To construct such a  concluding fact, a useful way is to borrow the subject from one fact and the ending conclusions from another fact.
question:
Fact 1: Electron transport is the final stage of aerobic respiration. 
Fact 2: Aerobic respiration is an oxidative process which uses oxygen as a final electron acceptor.
answer:
oxygen is used as an electron acceptor in respiration.


question:
Fact 1: Blood pH may become unbalanced if the rate of breathing is too fast or too slow. 
Fact 2: Acidity is measured with a pH meter or with pH paper strips.
answer:
Blood acidity may become unbalanced if the rate of breathing is too fast or too slow.


question:
Fact 1: high mountains with well-rounded peaks can be formed by collision of crustal plates. 
Fact 2: For big mountain background, check out the Himalayas .
answer:

The Himalayas can be formed by collision of crustal plates.