Consider the following statements about clouds : 1. Two major forms of clouds are stratiform and cumuliform. 2. According to the altitude, clouds are classified as high clouds, middle clouds and low clouds. 3. Stratus, nimbostratus and stratocumulus are types of high clouds. 4. Clouds having nimbo attached to their name produce precipitation. Which of the statements given above are correct ?

The correct answer is B, 1, 2 and 4. Only statement 3 is wrong, because stratus, nimbostratus and stratocumulus are low clouds, not high clouds. Statement 1 is correct: clouds take two basic forms, layered stratiform sheets formed by gentle lifting of air and heaped cumuliform clouds formed by rising convection currents. Statement 2 is correct: by height, clouds are grouped as high clouds (cirrus, cirrocumulus, cirrostratus, above about 6 km), middle clouds (altostratus, altocumulus) and low clouds, with towering cumulus and cumulonimbus spanning several levels. Statement 3 is wrong: the high group is the cirrus family, while stratus, stratocumulus and nimbostratus form below about 2 km. Statement 4 is correct: nimbus means rain cloud, so nimbostratus brings steady rain and cumulonimbus brings thunderstorms, heavy showers and hail. Option A is wrong because it omits the true statement 4. Option C is wrong because it omits the true statement 1. Option D is wrong because it includes the false statement 3. Exam tip: cirro = high, alto = middle, strato = low layers, nimbo = rain; cumulonimbus = thunder cloud.