Answer: Option B. -> False
:
B
Clear and transparent water is not always fit for drinking. Water might appear clean, but it may contain some disease causing micro-organisms and other dissolved impurities. So, it is essential to purify water before drinking. Water which is suitable for drinking is called potable water.

Answer: Option B. -> False
:
B

Clear and transparent water is not always fit for drinking. Water might appear clean, but it may contain some disease causing micro-organisms and other dissolved impurities. So, it is essential to purify water before drinking. Water which is suitable for drinking is called potable water.

Answer: Option B. -> False
:
B
Sewage water and industrial waste water contain a lot of chemicals, unused materials, and harmful microorganisms, and should not be directly disposed of into the rivers and lakes because they cause water pollution and contamination which is a threat to aquatic life. They should be first treated before dumping into these places.

Answer: Option B. -> Stone crushers and construction activities
:
A, B, C, and D

Air pollution occurs in different ways. Some of the causes are given below:
$\bullet$ Stone crushers give rise to a substantial quantity of dust emissions which creates health hazards.
$\bullet$ Municipal solid waste which is burned, adds particulate pollution to the air.
$\bullet$ Power plant industries also contribute to more than 40% of the population.
$\bullet$ Volcanic eruption is a natural phenomenon without human interference. It also releases large quantities of greenhouse gases and other pollutants.

Answer: Option A. -> True
:
A
Non-metal oxides react with water to form acids. Nitrogen dioxide which is a non metallic oxide reacts with water to form nitric acid.

Answer: Option C. -> Automobiles
:
C
Carbon monoxide $\left(\text{CO}\right)$ is a poisonous gas. The incomplete combustion of carbon-containing fuels, such as gasoline, natural gas, oil, coal, and wood leads to the formation of CO. Out of the given options, automobiles are the source of carbon monoxide $\left(\text{CO}\right)$ production.

Answer: Option C. -> Cremation of dead bodies 
:
A, B, C, and D
The pollution levels of Ganga river have been rising for many years. Throwing large quantities of garbage, untreated sewage, dead bodies, and many other harmful things directly into the river is the reason for the huge pollution. Millions of people live on the banks of the river which gives easy access to local village people to carry out their daily activities which directly contribute in polluting Ganga.

Answer: Option B. -> ultraviolet
:
B

The ozone layer is a region of the earth's stratosphere which absorbs the maximum ultraviolet radiations of the sun. The ozone layer protects life on earth by acting as a shield against ultraviolet rays. Ultraviolet radiation from the sun gets absorbed by the ozone layer keeping much of those harmful rays away from the organisms on the earth.

Answer: Option C. -> free of impurities
:
C

Pure drinking water is free of physical, chemical and biological impurities. Water which looks clear without any smell can still contain disease-causing micro-organisms. Boiling is a method to obtain safe drinking water at home.

Answer: Option C. -> potable
:
C

Water from natural bodies can contain micro-organisms that can cause diseases. So, it is essential to purify water before drinking. Water which is suitable for drinking is called potable water. Potable water has been filtered, cleaned, or treated to meet the standards for drinking water, meaning that it is reasonably clear of contaminants and harmful bacteria. This makes the water safe for drinking and cooking.