B. Because of the presence of hydrogen sulphide in Brass, it combines with oxygen in air and form water, evaporates. So remained sulphide is colourless in air .So Brass gets discoloured in the air.
Among the given choices, the only positive effect that may be thought off with the increase in level of CO2 in the atmosphere is the increase of plant growth. Carbon dioxide is an essential compound in the photosynthesis of plants. Therefore, the answer should be letter C.
The health of people damaged when the mercury is released into the atmosphere because of its toxic nature.
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What is the effect of mercury?</h3>
Mercury contamination is a great threat to public health and environmental because methylmercury easily enters the bloodstream which leads to damaged brain. It is considered toxic for the humans due to its damaging nature.
So we can conclude that the health of people damaged when the mercury is released into the atmosphere.
Learn more about mercury here: brainly.com/question/879
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