Clouds are the masses of small water droplets or tiny ice crystals.(A…

The correct answer is Option (1) → (A), (B) and (D) only

Note: The given answer is as per the official NTA Answer Key. However, none of the given options appears to be correct, because statement (D) describes cumulus clouds and not altocumulus clouds, as explained below.

Clouds are grouped by their form and the height at which they form:

• High clouds — cirrus, cirrostratus, cirrocumulus

• Middle clouds — altostratus, altocumulus

• Low clouds — stratocumulus, nimbostratus

• Clouds of vertical development — cumulus, cumulonimbus

(A) Clouds are classified according to their appearance and height. Correct. The names describe the look of the cloud (cirrus is feathery, cumulus heaped, stratus layered, nimbus rain-bearing) and the prefix ‘alto’ or ‘cirro’ tells the height.

(B) Cirrus clouds are high altitude clouds, which are usually feathery shaped and composed entirely of ice crystals. Correct. Cirrus clouds form at about 8,000-12,000 m, where it is very cold, so they are made of ice crystals and look thin, detached and feathery.

(C) Nimbostratus clouds are mid level clouds producing sporadic rain. Incorrect. Nimbostratus is a thick, dark, grey layer that gives continuous, steady rain or snow over a wide area, not sporadic showers. It is also usually counted among the low clouds, though its thick layer can reach the middle level.

(D) Altocumulus are the heap-like clouds having flat bases and rounded tops. Correct as per NTA; however, it is not correct as a description of altocumulus. Heap-like clouds with flat bases and rounded tops, looking like cotton wool, are cumulus clouds. Altocumulus are middle-level clouds seen as patches or rows of small, rounded white or grey masses, not as single heaps with a flat base.