Blue Baby Syndrome is caused by the contamination of

The correct answer is B, Nilgiris. The Nilgiri Biosphere Reserve spreads across Tamil Nadu, Kerala and Karnataka, meeting where the Western and Eastern Ghats join.

Set up in 1986, the Nilgiri Biosphere Reserve was India's first biosphere reserve and in 2000 became the first in India to join UNESCO's World Network of Biosphere Reserves. It includes protected areas such as Mudumalai, Wayanad, Bandipur, Nagarhole, Mukurthi and Silent Valley. It is home to the Nilgiri tahr, lion-tailed macaque and one of the largest populations of Asian elephants and tigers in India, and tribes such as the Todas, Kotas and Kurumbas live there.

A is wrong: Dehang Debang lies entirely in Arunachal Pradesh.

C is wrong: Nokrek lies in the Garo Hills of Meghalaya.

D is wrong: Seshachalam lies in the Eastern Ghats of Andhra Pradesh.

Exam tip: Nilgiri = first biosphere reserve (1986), three States; Agasthyamala spans Kerala and Tamil Nadu; Gulf of Mannar is the first marine biosphere reserve.

The correct answer is B, 1 and 3 only. Vermicompost is a nutrient-rich organic manure and crop rotation helps control pests and weeds, but organic farming does use biofertilizers and bio-pesticides.

Organic farming avoids synthetic fertilisers, chemical pesticides and genetically modified seeds. In their place it relies on manure, compost and vermicompost, which earthworms make from organic waste and which is rich in humus and plant nutrients, so statement 1 is correct. It actively uses biofertilizers such as Rhizobium, Azotobacter and blue-green algae, and bio-pesticides such as neem extracts and Trichoderma, which makes statement 2 wrong. Crop rotation breaks the life cycle of pests and weeds tied to one crop and also restores soil fertility, so statement 3 is correct.

A is wrong: statement 3 is also correct.

C is wrong: statement 2 is false and statement 1 is true.

D is wrong: statement 2 is false, because biological inputs are the core of organic farming.

Exam tip: organic farming says no to chemicals, not to biology; biofertilizers, bio-pesticides, compost and crop rotation are all part of it.

The correct answer is C, Nuclear. Nuclear power runs on uranium and thorium, mined minerals whose stock is finite, so it is a non-renewable source even though it is low in carbon.

A renewable source is one that nature replenishes on a human time scale, such as sunlight, wind, flowing water, biomass, tides and the earth's internal heat. Nuclear reactors split uranium-235 or, in breeder systems, use fuel made from thorium. Once the fuel is used, it does not return; it leaves long-lived radioactive waste. India's three-stage nuclear programme, planned by Homi Bhabha, aims to stretch its small uranium and large thorium reserves, but that does not make the fuel renewable.

Option A is wrong because solar energy comes from the sun, which will keep shining for billions of years. Option B is wrong because wind is produced by the uneven heating of the earth by the sun and never runs out. Option D is wrong because hydroelectric power uses water kept moving by the water cycle.

Exam tip: clean is not always renewable; nuclear is low-carbon but non-renewable.

The correct answer is A, environmentally responsible practices in electronics recycling industry. R2, short for Responsible Recycling, is a standard for environmentally responsible electronics recycling.

The R2 standard was developed with the support of the United States Environmental Protection Agency and is now managed by the non-profit SERI (Sustainable Electronics Recycling International). Recycling and refurbishing firms certified under R2 must handle used electronics safely, protect workers' health, secure the data on old devices, and track hazardous parts such as lead, mercury and cadmium so that they are not dumped or exported irresponsibly. It matters because e-waste is the world's fastest-growing waste stream. In India, e-waste is governed by the E-Waste (Management) Rules.

B is wrong: Ramsar wetlands are managed under the Ramsar Convention's own guidelines and the Montreux Record, not R2.

C is wrong: R2 has nothing to do with farming on degraded lands.

D is wrong: Environmental Impact Assessment follows national EIA rules, not the R2 code.

Exam tip: R2 = Responsible Recycling of electronics (SERI); e-Stewards is a similar e-waste standard.

The correct answer is D, 1, 2 and 3. All three statements are correct about PFAS, the so-called 'forever chemicals'.

PFAS are a large family of man-made chemicals built on very strong carbon-fluorine bonds. They resist water, grease and heat, so they are used in non-stick cookware, water-proof clothing, grease-proof food packaging and fire-fighting foams. Because the carbon-fluorine bond is so hard to break, PFAS hardly degrade in nature and have spread into soil, groundwater, drinking water and food. They build up in the blood and organs of animals and humans over time, and long exposure has been linked to liver damage, weaker immunity and some cancers.

A is wrong: it leaves out statement 3, which is also true.

B is wrong: it leaves out statement 1, which is also true.

C is wrong: it leaves out statement 2, the very reason they are called forever chemicals.

Exam tip: PFAS = 'forever chemicals', carbon-fluorine bonds, non-stick and water-proof products, persistent and bioaccumulative.