[Mission 2022] QUIZ – 2022: INSIGHTS STATIC QUIZ, 07 December 2021 – Environment – INSIGHTSIAS

Solution: b)

Biogas comprises primarily methane (CH4) and carbon dioxide (CO2) and may have small amounts of Nitrogen, Hydrogen, hydrogen sulphide and oxygen.

Solution: a)

• A sequence of organisms that feed on one another, forma food chain. In nature, two main types of food chains have been found: Grazing food chain and Detritus food chain.
• The grazing food chain starts with producers or autotrophs as base, which is consumed by heterotrophs. It is found in both Terrestrial and aquatic ecosystems.
• The Detritus food chain starts from dead organic ‘matter of decaying animals and plant bodies to the microorganisms and then to detritus feeding organism called detrivores or decomposer and to other predators.
• The two food chains are linked as the initial energy source for detritus food chain is the waste materials and dead organic matter from the grazing food chain.

Solution: c)

• Bio magnification stands for Biological Magnification, which means the increase of contaminated substances or toxic chemicals that take place in the food chains. These substances often arise from intoxicated or contaminated environments.
• The contaminants include heavy metals namely mercury, arsenic, pesticides such as DDT, and polychlorinated biphenyls (PCBs) compounds which are then taken up by organisms because of the food they consume or the intoxication of their environment.

• Pollutant needs to satisfy characteristics like long life, biologically active, soluble in fat etc. to make bio magnification possible.

Solution: c)

The mechanisms used by most mammals to regulate their body temperature are similar to the ones that we humans use. We maintain a constant body temperature of 37 degree C. In summer, when outside

temperature is more than our body temperature, we sweat profusely.

The resulting evaporative cooling, similar to what happens with a desert cooler in operation, brings down the body temperature. In winter when the temperature is much lower than 37 degree C, we start to

shiver, a kind of exercise which produces heat and raises the body temperature. Plants, on the other hand, do not have such mechanisms to maintain internal temperatures.

Thermoregulation is energetically expensive for many organisms. This is particularly true for small animals like shrews and humming birds. Heat loss or heat gain is a function of surface area. Since small animals have a larger surface area relative to their volume, they tend to lose body heat very fast when it is cold outside; then they have to expend much energy to generate body heat through metabolism. This is the main reason why very small animals are rarely found in polar regions.

Solution: d)

Phosphorous cycle is mainly terrestrial. The main storage for phosphorus is in the earth’s crust. On land phosphorus is usually found in the form of phosphates.

It occurs in large amounts as a mineral in phosphate rocks and enters the cycle from erosion and mining activities.

By the process of weathering and erosion phosphates enter rivers and streams that transport them to the ocean.

Being an important nutrient, phosphorous promotes eutrophication in lakes. Along with nitrogen related compounds it leads to undesirable situations like algal bloom.