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Almost all of the oxygen gas in today's atmosphere is present as a result of
a. outgassing from volcanoes.
b. aerobic respiration.
c. endosymbiosis.
d. photosynthesis.
Introduction:
The earth is the only planet, which supports life and this is because of the presence of life-supporting environment. Prokaryotes is said to be the first organism originated billion years ago and survived by using available resources like hydrogen sulfide from volcanoes and carbon dioxide in the atmosphere. Photosynthetic bacteria performed anaerobic respiration as there was no oxygen in the atmosphere.
Answer to Problem 1MC
Correct answer:
Almost the entire amount of oxygen gas present in today’s atmosphere is due to photosynthesis.
Explanation of Solution
Explanation for the correct answer:
Option (d) is given that photosynthesis is the source of almost all the oxygen present in today’s atmosphere. Photosynthetic bacteria used water (H2O) to carry out the photosynthesis process and as a result, oxygen is released abundantly into the atmosphere. Carbon dioxide and water are used to produce carbohydrates where oxygen is released as one of the end products. Hence, option (d) is correct.
Explanation for incorrect answers:
Option (a) is given that outgassing from volcanoes is the source of oxygen content present in today’s atmosphere. As volcanoes erupt, outgassing provided the hydrogen required for photosynthesis process. But oxygen is not the end product when hydrogen sulfide from volcanoes is used. So, it is an incorrect option.
Option (b) is given that aerobic respiration is a process which breaks down complex substances in the presence of oxygen to result in simple substances in order to obtain energy. It is the process which uses oxygen and it does not release oxygen. So, it is an incorrect option.
Option (c) is given that endosymbiosis occurs when two organisms live in a harmonious relationship where one organism lives inside another organism. So, it is an incorrect option.
Hence, options, (a), (b), and (c) are incorrect.
Thus, it can be concluded that the abundant oxygen content in today’s atmosphere is due to the ability of organisms, which use water for photosynthesis and release oxygen as one of the products.
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Chapter 18 Solutions
BIOLOGY:LIFE ON EARTH-W/ACCESS
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Concepts of BiologyBiologyISBN:9781938168116Author:Samantha Fowler, Rebecca Roush, James WisePublisher:OpenStax College