Questions

The law of conservation of mass states that in any closed system the mass of the system is neither created nor destroyed over time i.e, the mass cannot be changed overtime.

Hence, the given statement is true.

When you breathe in air through your nose, it contains lots of tiny things, like dust, dirt, germs, and pollen.

The air enters our body through the nose. However, before it enters the lungs, it must be heated and purified. Many dust particles that enter along with the air are removed in the nose by mucus and thus it protects lungs.

Demand is said to be inelastic, when the demand for the good doesn't change much or it is negotiable when the price of the good changed.

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