Chapter 16: Environmental Issues

Ans: Correct option is c.

Toxic pollutants which cannot be degraded or decomposed in a natural way into less harmful components are called as non-biodegradable pollutants i.e., they would not decompose when thrown away on ground. The primary source of non-biodegradable pollutants are humans because of the consumption rates of these being so high. These pollutants include various metals like arsenic, polythene, mercury; plastic; and synthetic fibers. 

Ans:  Correct option is a.

Particulate matter that leads to major air pollution can be differentiated into two categories:

1. Settable particulate matter; which is larger than 10 diameters.

2. Suspended particulate matter; which is less than 10 diameters.

According to the Central Pollution Control Board, particles having a diameter 2.5 mm and lesser are hazardous to the human health as they can pass deeper into the lungs causing many breathing and respiratory problems, and in adverse conditions it can even lead to be fatal.

Ans: Correct option is d. 

Styrofoam, a type of polystyrene foam, is the material usually used for soundproofing rooms like auditorium, assembly hall and film lobby. Earplugs are made of fine glass wood or cottonwood impregnated with wax while ear covers plastic froth for engrossing sound. 

Ans: Correct option is b. 

Compressed natural gas or CNG is primarily methane and is considered as the most suitable alternative to petrol or diesel in terms of the impact fuels have on the environment. In 2002, as ordered by the Indian government, public transport vehicles in Delhi switched to CNG as it leads to less pollution and efficiently burns producing less pollutants.

Ans: Correct option is c.

Eichhornia, otherwise known as water hyacinth, is famously known as the world's most problematic aquatic weed. It is also known as terror of Bengal because of its high rate of growth. It can grow rapidly and cover the surface of water bodies completely to choke them. It can cause serious threats to the aquatic fauna and flora.

Ans: Correct option is d.

The increase in concentration of a toxicant as we go at successive trophic levels is known as bio magnification. This happens because toxic substances accumulated by an organism are passed to the next trophic level as it cannot be metabolized or excreted along the food chain. This phenomenon is popularly seen in accumulations of Mercury and DDT. 

Ans:  Correct option is a.

Dichloro-diphenyl trichloroethane, popularly known as DDT is a colorless, tasteless and odorless crystalline chemical compound and is not found naturally as it is synthesized. It was developed as an insecticide but ultimately became famous for its environmental impacts. 

Ans: Correct option is c.

Bones are the hardest tissues in the body which are primarily made up of proteins like collagen and many inorganic compounds composed of calcium and phosphates. The inorganic content in bones is much higher as compared to the other constituents of this tissue. However, cotton, paper, and jute are made up of mostly organic matter and hence, can be easily degraded by microbes. But bones, due to the presence of a lot of inorganic content, take a very long time for biodegradation.

Ans:  Correct option is c.

Oxygen content is not measured using Dobson units(DU) but it is used to represent ozone(O₃) in the atmosphere thickness or concentration.Accordingly, it has been established that the thickness of ozone is more around equators in comparison to poles.

Ans: Correct option is a.

Burning coal is one of the major causes of indoor chemical pollution. It leads to release of excessive carbon content in the atmosphere that combines with oxygen to later form carbon dioxide. It may even result in formation of carbon monoxide when oxygen is provided in a limited amount which is a threat to human health.