Methane in the polluted air reacts with oxygen to form which of the following compounds?

What is green fuel? Give information about waste recycling.

If the $pH$ of water increases above ......,the effectiveness of chlorination in water is reduced.

Given below are two statements.
Statement $I:$ In polluted water,values of both dissolved oxygen and $BOD$ are very low.
Statement $II:$ Eutrophication results in a decrease in the amount of dissolved oxygen.
In the light of the above statements,choose the most appropriate answer from the options given below.

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.

Which of the following is harmful to calcium-containing structures and is responsible for causing cough and throat irritation in humans?