I think the answer is that pressure builds and causes the heart to work harder.
It has been projected that by 2025 b. 2 out of 3 people will suffer from water shortages.
The problem of shortage of water will happen to the altered weather patterns, depletion of ground water, pollution of water, and due to demand-supply problem in increased population sizes of humans. The present scenario is emphasizing more on the sustainable use of water for agricultural and industrial purposes to promote water conservation. This will reduce the proportion of affected people in the future.
I'd go with the third one because the products of both of them are oxygen and carbon dioxide.
The answer is D its the right answer because on the moon there is not oxygen for it to reach that state
