One of the limiting factors in human physical performance is the amount of oxygen that is absorbed by the muscles from the bloodstream. accordingly, entrepreneurs have begun selling at gymnasiums and health clubs bottles of drinking water, labeled “superoxy,” that has extra oxygen dissolved in the water. such water would be useless in improving physical performance, however, since the only way to get oxygen into the bloodstream so that it can be absorbed by the muscles is through the lungs.
which of the following, if true, would serve the same function in the argument as the statement in boldface?
(a) the water lost in exercising can be replaced with ordinary tap water
(b) the amount of oxygen in the blood of people who are exercising is already more than the muscle can absorb
(c) world-class athletes turn in record performance without such water
(d) frequent physical exercise increases the body’s ability to take in and use oxygen
(e) lack of oxygen is not the only factor limiting human physical performance

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.