The correct option is (a).
Explanation
A desert is primarily defined as a region with extreme aridity (water deficit). While often associated with heat, the scientific classification of a desert depends on precipitation levels and the resulting adaptation of vegetation (xerophytes), rather than temperature alone.
Statement 1 is Correct:
Deserts are characterized by very low rainfall (typically less than 25 cm annually) and high evaporation rates. Consequently, the vegetation is scanty and consists mostly of xerophytic plants (such as cacti, acacia, and thorny bushes) adapted to conserve water.
Statement 2 is Incorrect:
Deserts are not always associated with extremely high temperatures. They are classified into two types based on temperature: Hot Deserts (e.g., Sahara, Thar) and Cold Deserts (e.g., Ladakh, Gobi, Antarctica). Cold deserts experience freezing temperatures but share the characteristic of extreme aridity.
Statement 3 is Incorrect:
Agriculture is not impossible in deserts if water is available. With the help of irrigation systems (canals, tube wells) and oases, agriculture is practiced in many desert regions. For example, the Indira Gandhi Canal has transformed parts of the Thar Desert into agricultural land.
Key Takeaway:
The defining characteristic of a desert is aridity (precipitation deficit), not high temperature. Deserts can be either hot or cold, and agriculture is possible with appropriate irrigation.