24. NCERT Exemplar VI

3 m.

1. Which of the following is a recently originated problem of environment?

2. When we breathe in air, nitrogen also goes inside along with oxygen. What is the fate of this nitrogen?

It is absorbed only by the nasal cells.
Nitrogen concentration is already more in the cells so it is not at all absorbed.
It moves along with oxygen into the cells.
It comes out with the \(CO_2\) during exhalation.

3. Top-soil contains the following.

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