Match List-I with List-II and choose the correct answer from the options given below.

List - I	List - II
(a) Allen's Rule	(i) Kangaroo rat
(b) Physiological adaptation	(ii) Desert lizard
(c) Behavioural adaptation	(iii) Marine fish at depth
(d) Biochemical adaptation	(iv) Polar seal

To match each type of adaptation in List‑I with the most appropriate example in List‑II, we consider the defining characteristic of each adaptation.

Allen’s Rule states that endothermic animals in colder climates tend to have shorter limbs and extremities to minimize heat loss. Among the options, the polar seal lives in a cold polar environment and exhibits a compact body shape, making it the classic example of Allen’s Rule. Hence, (a) ↔ (iv).

Physiological adaptation involves internal bodily changes that help an organism survive under specific conditions, such as specialized kidney function to conserve water. The kangaroo rat lives in arid deserts and possesses highly efficient kidneys that concentrate urine, a clear physiological adaptation to water scarcity. Therefore, (b) ↔ (i).

Behavioural adaptation refers to actions or patterns an organism adopts to cope with its environment. A desert lizard often changes its activity pattern, seeking shade or burrowing during the hottest part of the day, which is a behavioural strategy to avoid excessive heat. Thus, (c) ↔ (ii).

Biochemical adaptation includes changes at the molecular level, such as enzymes that function under high pressure or extreme temperatures. A marine fish at depth must cope with high hydrostatic pressure; it often has pressure‑resistant enzymes and membrane proteins, exemplifying a biochemical adaptation. Consequently, (d) ↔ (iii).

Putting these pairings together gives the final matching: a‑iv, b‑i, c‑ii, d‑iii.