Given below are two statements, one is Assertion (A) and the other is Reason (R). Select the correct answer from the codes given: Assertion (A) : Uttarakhand is rich in forest and bio-diversity. Reason (R) : Topography and climate primarily determine the forest and bio-diversity.
- (a)Both (A) and (R) are true, but (R) is not the correct explanation of (A)
- (b)Both (A) and (R) are true and (R) is the correct explanation of (A)
- (c)(A) is true, but (R) is false
- (d)(A) is false, but (R) is true
Correct — B, Both (A) and (R) are true and (R) is the correct explanation of (A).
Statement (A) holds. About 45 per cent of Uttarakhand's geographical area carries forest cover in Forest Survey of India assessments, and its protected areas run from the sal country of Corbett in the foothills to Gangotri and Nanda Devi near the glaciers.
Statement (R) is the standard account of why natural vegetation differs from place to place. Temperature and rainfall set the outer limits of what can survive; altitude, slope and the direction a slope faces decide how much heat, moisture and soil any particular site actually receives.
So the link here is causal, not coincidental — (R) is the correct explanation of (A). Uttarakhand rises from roughly 200 m in the Bhabar to Nanda Devi at 7,816 m, and that relief stacks tropical, temperate and alpine conditions inside one small state.
Carry this away: variety of habitat comes first, and variety of species follows from it. Where terrain and climate create many different living conditions close together, many kinds of plants and animals find a place.
- (a)Both (A) and (R) are true, but (R) is not the correct explanation of (A) — The first clause is fine — both statements are true. The option fails on its second clause. Topography and climate are not a separate fact standing beside Uttarakhand's forest wealth; they are what produces it.
This option is the right answer when two true statements sit side by side with no causal link between them — say, that Uttarakhand is heavily forested and that it was carved out of Uttar Pradesh in November 2000. Both true; neither explains the other.
- (c)(A) is true, but (R) is false — (A) is true, so the first half is safe. Choosing this option means rejecting (R) — claiming that terrain and climate do not lead in deciding where forests and species occur, which reverses the usual explanation of natural vegetation in physical geography.
This option is the right answer when a sound observation is coupled to a false or inverted mechanism — for instance, a true statement about hill vegetation joined to the claim that altitude has no bearing on temperature.
- (d)(A) is false, but (R) is true — (R) is true, but this option asks you to reject (A). Forest covers close to half of Uttarakhand's area, and its national parks span habitats from sal forest in the Bhabar to alpine meadow and glacier country in the north.
This option is the right answer when a sound general principle is attached to a factually wrong particular claim. Here it is the particular claim, about Uttarakhand, that holds up.
Natural vegetation is not scattered at random. At the regional scale two controls dominate: climate, chiefly temperature and rainfall, and topography — altitude, steepness, and the direction a slope faces.
Climate sets the outer limits of what can survive. Terrain then redistributes heat, water and soil within those limits, so two sites a kilometre apart can carry different forests.
Where terrain is varied, conditions change over short distances. Many plant communities, and the animals that depend on them, can therefore live close together — which is what makes such country species-rich.
This is the reasoning behind the ecological richness of mountain country. Steep relief means a traverse of a few dozen kilometres can cross conditions that, on a plain, would be separated by thousands of kilometres of latitude.
Uttarakhand is a compact working example. Within one state lie the Terai and Bhabar plains, the Shiwalik and Lesser Himalayan ridges, the Great Himalaya, and inner valleys lying in the rain shadow of the high range.
The same logic underlies how India's forest types are classified and why protected areas in the state are strung along an altitudinal ladder rather than clustered in one belt.
- About 45 per cent of Uttarakhand's geographical area is under forest cover in Forest Survey of India assessments.
- The land rises from roughly 200 m in the Bhabar and Terai to Nanda Devi at 7,816 m, the highest peak lying wholly within India.
- Broadly with rising altitude the forest changes from sal to chir pine, then banj oak, then deodar, spruce and fir, and finally birch near the treeline.
- Above the treeline, tree growth gives way to alpine meadows locally called bugyals.
- In the mid-hills, cooler and moister north-facing slopes typically carry banj oak while sunnier south-facing slopes carry chir pine.
- Jim Corbett National Park, notified in 1936 as Hailey National Park, was India's first national park.
- Nanda Devi and Valley of Flowers National Parks are inscribed together on the UNESCO World Heritage List.
Altitude and aspect change temperature and moisture over a few dozen kilometres, so belts a plain would spread across thousands of kilometres of latitude are stacked inside one state. That is why (R) explains (A).
- Judging (R) only as a standalone sentence and then forgetting the second test — whether it actually produces (A). A reason that is true but inert still lands on option (a).
- Reading 'primarily determine' as 'exclusively determine'. Soil, drainage and human use also shape forests; the statement claims only that topography and climate lead, which they do at the regional scale.
- Assuming a state-level assertion needs a state-specific reason. A general geographical principle can be the correct explanation of a particular case.
- Doubting (A) because the state is mountainous and rocky. The rugged terrain is the source of the diversity here, not an obstacle to it.
- Picking the option position rather than the wording. The four verdicts appear in different orders in different papers, so read the text of the option before marking it.
The Assertion-Reason format asks two things in sequence: is each statement true on its own, and does the second one cause the first? The options keep those judgements apart, which is how a true reason can still be the wrong reason.
The same idea also turns up as a plain single-best-answer item — why the Himalaya is species-rich, why oak and pine sort themselves onto opposite slopes, or which vegetation belt sits immediately above another.
A third form is the map or pair-matching item, asking you to place a species or a park in the right altitudinal belt.
UPPSC_2025_PRE_GSI_Q212025The closest match: the same Assertion-Reason device and the same causal chain, with vegetation variety explained by conditions changing with height. It differs in scale and in the named cause — that item asks about the Himalaya as a whole and names altitude-linked climate alone, while this one covers one state and pairs topography with climate.
UPSC_2011_GS1_Q242011Same underlying subject — why the Himalayan range is species-rich — but built as a single-best-answer item rather than an Assertion-Reason pair, and it directs the explanation towards biogeography, the meeting of different zones, rather than to relief and climate as such.
UPSC_2003_GS1_Q1102003Same Assertion-Reason machinery on forests, but with the two halves pulling apart: the reason there concerns the primary productivity of tropical rain forest while the assertion makes a claim about farmland after clearance, so each half has to be tested before the causal link is judged.
UPSC_1996_GS1_Q491996Same format on a forest ecosystem, and a useful contrast in what a 'reason' is doing. The reason there states a function of mangroves — shoreline stabilisation — rather than a cause of their being specialised coastal ecosystems, which is exactly the distinction the 'not the correct explanation' option exists to catch.
UKPSC_2016_PRE_PaperII_Q562016Same commission and the same Assertion-Reason device applied to Uttarakhand, but the subject is hill out-migration and land degradation rather than forests, and the causal arrow there runs from human movement to land condition, not from physical setting to living things.
- practice — not a real PYQ
A traverse of only a few dozen kilometres in Uttarakhand can pass from sal forest to alpine meadow. Which one of the following is the most appropriate reason for this?
- (a)The state receives uniform rainfall through the year
- (b)Temperature falls sharply with altitude, while moisture and exposure change with slope and aspect
- (c)The soils of the state are derived from a single parent rock
- (d)The higher reaches of the state are free of human settlement
Answerb — Each few hundred metres of climb lowers temperature and alters exposure and soil moisture, so plains, temperate and alpine growing conditions are stacked vertically within a short horizontal distance.(a) fails because rainfall here is strongly monsoon-seasonal, not uniform. (c) fails because the state's rocks and soils are varied, and soil is a secondary control at this scale. (d) fails because high valleys carry villages, grazing and pilgrim routes.
- practice — not a real PYQ
Assertion (A): In the mid-hills of Uttarakhand, banj oak tends to occupy cooler, moister north-facing slopes while chir pine occupies sunnier south-facing slopes. Reason (R): The direction a slope faces changes the sunlight and the soil moisture a site receives. Select the correct answer from the codes given below:
- (a)Both (A) and (R) are true and (R) is the correct explanation of (A)
- (b)Both (A) and (R) are true, but (R) is not the correct explanation of (A)
- (c)(A) is true, but (R) is false
- (d)(A) is false, but (R) is true
Answera — The pattern in (A) is the observed one, and (R) states the mechanism behind it: a south-facing slope in the northern hemisphere takes more direct sun, dries faster and suits chir pine, while the shaded slope holds moisture and suits oak.(b) fails because the two halves are causally joined, not merely both true. (c) fails because (R) is sound. (d) fails because (A) is sound.
- practice — not a real PYQ
India's first national park, notified in 1936 and lying in present-day Uttarakhand, is
- (a)Rajaji National Park
- (b)Jim Corbett National Park
- (c)Gangotri National Park
- (d)Valley of Flowers National Park
Answerb — It was notified in 1936 as Hailey National Park and later renamed after Jim Corbett; it sits in the sal-dominated foothill belt of the state.(a), (c) and (d) are all national parks of Uttarakhand, but each was notified decades after 1936, and Gangotri and Valley of Flowers lie in the high Himalaya rather than the foothills.
- practice — not a real PYQ
In Uttarakhand, the term 'bugyal' refers to
- (a)Glacial lakes dammed by moraine
- (b)High-altitude meadows lying above the treeline
- (c)Dense sal forests of the Bhabar belt
- (d)Terraced rice fields of the Terai
Answerb — Bugyals are the alpine grasslands above the upper limit of tree growth, used as summer grazing; Dayara and Bedni are among the better-known ones.(a) names moraine-dammed lakes, a separate glacial landform. (c) describes the foothill sal belt, which lies far below the treeline. (d) is wrong on two counts — the Terai is flat rather than terraced, and it is nowhere near the alpine zone.