Weathering: physical, chemical, and biological

Correct answer: C. Exfoliation

Thermal change or pressure release can peel outer layers. In exams onion like layers indicate exfoliation.

Correct answer: D. Organisms releasing acids to dissolve minerals

Organic acids from organisms can chemically alter minerals. In exams do not limit biological weathering to roots only.

Correct answer: A. It remains nearly unchanged

In physical weathering size changes but mineral composition mostly remains the same. For exams remember composition versus size.

Correct answer: B. Strong combination of biological and chemical weathering

Forest adds organic acids and root action while rainfall increases chemical reactions. In exams study rainfall and organisms together.

Correct answer: C. Granular disintegration

Different minerals respond differently to heat causing grains to separate. For exams treat multi mineral rocks as the clue.

Correct answer: D. Quartz

Quartz is generally more stable and resistant under common conditions. In exams connect quartz with sandy residues.

Correct answer: A. Carbonation

Calcite can dissolve easily in mildly acidic water. For exams link calcite and limestone with carbonation.

Correct answer: B. Fresh rock is repeatedly exposed and further weathered

Removal exposes fresh rock surfaces so weathering can continue. In exams connect slopes with removal of material.

Correct answer: C. Long stable surface and sufficient moisture

Direct answer: Option C, a long-stable surface with sufficient moisture. Weathering depth means how far weathering has progressed below the ground surface. Chemical weathering needs water, and it also needs time to act. On a stable surface, soil and rock remain in place for a long period instead of being quickly removed. Moisture can then enter cracks and pores repeatedly, carrying chemical reactions deeper. Option C is correct because it supplies both important factors: long duration and adequate water. Option A is wrong because very little rainfall provides little water, while rapid removal prevents a deep weathered layer from developing. Option B is wrong because continuous ice cover and no water flow greatly restrict the movement of liquid water and chemical reactions. Option D is wrong because fresh lava is continuously added, so an old stable weathering profile cannot develop easily. Memory cue: deep weathering needs time, stability and moisture.

Correct answer: D. Large daily temperature range and low moisture

Low moisture reduces chemical reactions and temperature range increases physical stress. For exams remember desert conditions.

Correct answer: A. Weathering creates loose material that gravity can move downslope

Weathering weakens and loosens material on slopes. In exams view weathering as preparation for mass movement.

Correct answer: A. Because lack of water limits chemical alteration

Water acts as both a solvent and a medium for chemical reactions in weathering. When water is scarce, processes such as hydration, hydrolysis and solution become very slow, so thick chemically weathered soil develops less readily. Mechanical weathering may break rocks through thermal expansion or salt crystallisation, but it does not itself cause chemical alteration. Exam tip: associate arid climates mainly with mechanical weathering and limited chemical weathering.

Correct answer: B. Thick tree roots growing in cracks

Thick roots can widen cracks and break rocks. In exams consider root pressure a mechanical biological effect.

Correct answer: C. Clay minerals

Feldspar hydrolysis can produce clay like minerals. In exams remember feldspar forming kaolin like products.

Correct answer: D. Structure with joints and faults

Joints and faults provide pathways for water and air to depth. In exams treat structural weakness as a weathering route.

Correct answer: A. Physical weathering

Physical weathering reduces size but usually does not alter composition. For exams remember it as mechanical breakdown.

Correct answer: A. After cracks form water enters and alters minerals

Breakage increases surface area and then water speeds chemical alteration. For exams see processes as connected as well as separate.

Correct answer: B. Because mineral composition cracks and climate also control the rate

Weathering results from many factors not hardness alone. In exams remember structure minerals and climate together.

Correct answer: C. Intense chemical weathering and long lasting moisture

High moisture and heat drive mineral alteration to depth. For exams link deep weathering mantle with humid tropical climate.

Correct answer: D. Slow because entry paths and surface area are limited

With few cracks entry of water and air is limited. In exams connect lack of structural weakness with slow weathering.

Correct answer: A. Organisms can alter rocks mechanically and chemically

Roots exert pressure and microorganisms may release acids. In exams remember both forms of biological weathering.

Correct answer: B. Solution

In solution water can dissolve and carry soluble substances. For exams this is the most direct chemical process.

Correct answer: A. Weathering weakens rocks and makes later erosion easier

Weathering prepares rock for erosion by breaking and altering it. In exams treat it as preparation for landform formation.

Correct answer: A. Removal of silica and bases by leaching

Heavy rainfall removes soluble materials by leaching and leaves iron aluminium residues. In exams link laterite with humid tropical weathering.

Correct answer: B. Deep chemical weathering in jointed granite followed by removal

Deep weathering along joints leaves corestones and tors appear after loose material is removed. For exams remember tors with granite and joint controlled weathering.