Environment and Ecology Mixed Practice — MCQs with Answers (Set 16)

The CCAC was founded in 2012 by Bangladesh, Canada, Ghana, Mexico, Sweden, the United States, and UNEP.

H-CNG currently costs more than plain CNG, mainly due to hydrogen production and blending costs.

The Automotive Research Association of India (ARAI) and Indian Oil Corporation Ltd (IOCL) jointly tested H-CNG in buses.

H-CNG cuts CO sharply but does not eliminate it. The other three claims about H-CNG are correct.

Hydrogen can be blended with CNG up to roughly one-fifth by volume for use as bus fuel.

Tests by ARAI and IOCL found H-CNG can reduce carbon monoxide emissions by up to about 70%, but not eliminate them.

Unmineable coal seams can adsorb CO2, but they hold less capacity than oil, gas, or saline sites, limiting commercial-scale projects.

Deep saline aquifers underlie huge areas, giving them by far the largest total CO2 storage capacity of the three site types.

A safe storage site needs a porous reservoir rock to hold the CO2, sealed by an impermeable cap rock on top.

Below about 800 metres, pressure and heat make CO2 a supercritical fluid. It is dense like a liquid. Much more CO2 fits in rock pores in this state.

The IPCC range at costs below 100 US dollars a tonne is 0.3 to 1.8 billion tonnes of CO2-equivalent a year. The wider technical range for 2050 is 0.2 to 6.6 billion tonnes.

Terra Preta means dark earth. Amazonian communities added charcoal and waste to poor soil. These soils still hold far more black carbon than the soils around them.

Open burning sends the stubble’s carbon back to the air as CO2. Pyrolysis keeps about half of the carbon as stable biochar, per the European Biochar Certificate. The rest leaves as gas.

The IPCC says effects vary with the biochar and the soil. Gains are most likely in sandy and acidic soils with low nutrient-holding power.

Vertical farming stacks crops in layers, cutting land use while enabling efficient water use and minimal pesticide need.

Legume roots host Rhizobium bacteria. The bacteria fix nitrogen from the air. A review says this enriches the soil and reduces the need for synthetic fertilisers.

A tensiometer measures soil water tension. That shows how tightly the soil holds its water. Farmers use the reading to decide when to irrigate.

A review in Global Challenges says crop rotation disrupts pest and disease cycles. It also says diverse cropping systems support natural pest predators. These help control pests and reduce the need for chemical pesticides.

UPSC’s official answer key for CSP 2020, General Studies Paper I, Set A, gives option (a), 1, 2 and 3 only. Crop diversification, legume intensification and tensiometer use count. Vertical farming is not in the key.

India’s biofuel policy also allows surplus sugarcane and grains to be diverted to ethanol, when there’s a genuine production surplus.

Approved feedstocks are either damaged, rotten, or surplus material unfit for eating, or crops grown specifically for industrial use.

The policy text does not give a reason for leaving out these two crops. They are simply not named. Exam answers explain the gap through food security, since both are food and protein crops. Treat that as the exam reading, not wording from the policy.

Four items are named in the policy. Cassava is a starch-containing material. Damaged wheat is a damaged food grain. Rotten potatoes are named directly. Sugar beet is a sugar-containing material. Groundnut seeds and horse gram are not on the list. So the answer is 1, 2, 5 and 6 only.

Biochar’s benefits depend heavily on the feedstock and pyrolysis conditions used to make it, so quality varies between batches.

Biochar is also used in water filtration and environmental remediation, beyond its role as a soil or growing-medium amendment.