Lead is considered as

How is non-degradable industrial solid waste disposed of?

Which of the following compounds is the most harmful component of photochemical smog?

The acids responsible for acid rain are ......... .

Determine whether the following statements are true or false:
$(1)$ The lowest region of the atmosphere where all living organisms,including humans,reside is called the troposphere.
$(2)$ The troposphere extends up to a distance of $25 \ km$ from sea level.
$(3)$ The region between $10 \ km$ and $50 \ km$ from sea level is called the stratosphere.
$(4)$ The ozone layer that protects living organisms is located in the troposphere.

Consider the following.
Assertion $(A)$: $CO$ is poisonous to living beings.
Reason $(R)$: $CO$ binds to haemoglobin forming carboxyhaemoglobin,which is less stable than oxygen-haemoglobin complex.
Correct answer is