Which one of the following statements is wrong?
- AMost of the forests have been lost in tropical areas.
- BThe greenhouse effect is a natural phenomenon.
- CEutrophication is a natural phenomenon in freshwater bodies.
- DOzone in the upper part of the atmosphere is harmful to animals.
Show answer and explanation
Correct answer: (d) Ozone in the upper part of the atmosphere is harmful to animals.
Explanation
Statement (d) is wrong: ozone in the upper atmosphere (the stratosphere) is "good ozone". It absorbs most of the Sun's harmful ultraviolet rays, which cause skin cancer and cataracts. Ozone is harmful only near the ground, in the troposphere, where it is a pollutant.
The other statements are correct: most forest loss is in the tropics; the greenhouse effect is natural (without it the Earth would be about −18 °C instead of 15 °C); and eutrophication happens naturally as lakes age, though human pollution speeds it up.