Reconciling cash book and passbook differences

An outwash plain is a broad, gently sloping area built from sand, gravel and other sediments carried away from a glacier by meltwater streams. The deposits are therefore glaciofluvial, meaning they are produced by both ice-related meltwater and flowing water. Option A is correct. An oxbow lake is fluvial, a sea arch is coastal erosion, and loess is wind-blown silt.

Direct answer: D, river deposition. During a flood, water rises and spreads over the river banks. As it leaves the channel, its speed and carrying power decrease suddenly. The heavier particles, such as sand and coarse silt, settle first near the channel. Repeated floods build raised embankments beside both banks; these are natural levees. A is erosion by moving ice, B is the wearing of surfaces by wind-blown particles, and C is erosion caused by waves along a coast. None of these processes explains raised river banks. Memory cue: floodwater slows outside the channel, so sediment drops beside the river and builds a natural levee.

Direct answer: A is correct. Water vapour enters the atmosphere mainly through evaporation, in which liquid water changes into vapour. Coastal areas lie close to seas or oceans, which provide a large and continuing moisture source. Winds moving from the sea towards land can carry this vapour inland, so humidity is often high near the coast. The exact amount also depends on temperature, wind and local weather, so “usually” does not mean every coastal place is always equally humid. B is wrong because coastal regions have air. C is wrong because coastal soil is not always frozen. D is wrong because nitrogen in seawater has no direct role in producing atmospheric water vapour. A correctly identifies evaporation and marine moisture supply. Memory cue: “Near a large water body, evaporation feeds humidity.”

Direct answer: The troposphere is higher over the equator because stronger solar heating produces stronger convection, so option B is correct. The equatorial surface receives more direct sunlight on average. This warms the ground and the air above it. Warm air expands, becomes less dense, and rises. Continuous rising and mixing are called convection. These stronger vertical motions extend the troposphere to a greater height than in colder polar regions. Option A is wrong because the equator is not colder; it receives intense heating. Option C is wrong because the equatorial region has abundant air. Option D is wrong because ozone is not the main reason for the height difference. The important chain is: stronger sunlight → warmer air → expansion and rising → stronger convection → a higher tropopause. Memory cue: “More heat makes air rise higher.”

A, convection. The surface warms the air near it; the warmed air expands, becomes less dense, and rises. Its movement transfers heat through the air, while cooler, denser air moves in to replace it. This circulation is convection and helps drive weather processes in the troposphere.