The correct option is D a - iv, b - i, c - ii, d - iii
(a) Allen’s rule describes a morphological adaptation in animals stating that mammals living in colder climates (polar regions) adapt to the surroundings by having shorter extremities (limbs and ears). This helps them to reduce heat loss from the body.
(b) Kangaroo rat is a rodent that lives in the hot and dry climate of the North American deserts. To be able to survive in such extreme climatic conditions, kangaroo rats have multiple physiological and morphological adaptations that allow them to fight with the extreme conditions of the desert.
Deserts have massive scarcity of water and still kangaroo rats are able to survive in such conditions as they oxidise the fats to obtain water that is used for its metabolic functions.
(c) Desert lizards control their body temperature via behavioural adaptations. When the desert becomes too hot during the day, it hides in shady places to keep itself cool. Whereas when the temperatures fall below its comfort zone, especially during the winter, it basks in the sun to keep itself warm.
(d) Some fishes have also evolved to survive pressure which is 100 times more than the atmospheric pressure. Presence of TMAO – Trimethylamine oxide in deep-sea fish prevents the distortion and compression of proteins and other vital molecules within the body under intense external pressure. It is a biochemical adaptation.