Our Environment And Its Management Test - 1

The biological treatment of waste water makes use of aerobic and anaerobic bacteria at secondary treatment level.

Mesopelagic zone is also called the twilight zone. The mesopelagic zone still receives some light, but it is not enough to fuel photosynthesis. Bioluminescence is prevalent here, helping creatures disguise their silhouettes from animals below them.

Burning of fossil fuels leads to release of carbon dioxide.
Radioactive wastes are emitted by nuclear power plants.

Aircraft jet engines directly emit aerosol particles and condensable gases.
All these three cause environmental pollution.

The greenhouse effect is a warming of Earth's surface and the air above it. It is caused by gases in the air (like carbon dioxide) that trap energy from the sun. Green house gases are responsible for greenhouse effect.

All the statements are correct. Decomposition of biodegradable wastes leads to foul smell.
Dumping of industrial wastes reduces the fertility of soil and leads to reduction in crop yields.

Breeding of flies in huge quantity carries germs and spreads diseases.

Dumping of waste into water bodies leads to water pollution and is responsible for spreading of various water-borne diseases.

Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion. Under the original Montreal Protocol agreement (1987), developed countries were required to begin phasing out CFCs in 1993 and achieve a 20% reduction relative to 1986 consumption levels by 1994 and a 50% reduction by 1998.

The food chains involving various living organisms in a community can be represented graphically by drawing pyramids, which are known as ecological pyramids. Thus, ecological pyramids are another way of representing the energy transfer taking place in a food chain in a community. At each successive trophic level, there is gain of weight rather than loss.

Eutrophication is when the environment becomes enriched with nutrients. This can be a problem in marine habitats such as lakes as it can cause algal blooms. Fertilisers are often used in farming. Sometimes, these fertilisers runoff into nearby water, causing an increase in nutrient levels.

Incomplete combustion of coal leads to the formation of carbon monoxide. Carbon monoxide is toxic to cells and can cause death of human beings.