Silkworm
Explanation
Metamorphosis is a biological process in the development of certain animals, involving a conspicuous and abrupt change in the animal's body structure through cell growth and differentiation. It typically occurs after birth or hatching and transforms the organism from an immature form (larva) into an adult form.
Option-wise Analysis
- Human: Incorrect. Humans undergo direct development. The young ones (infants) physically resemble the adults at birth, possessing the same basic body structure without undergoing intermediate larval or pupal stages.
- Cow: Incorrect. Cows are viviparous mammals that undergo direct development. The calf born resembles the adult cow in structure and form.
- Silkworm: Correct. The silkworm (Bombyx mori) exhibits indirect development involving metamorphosis. Its life cycle consists of four distinct stages: Egg → Larva (Caterpillar) → Pupa (Cocoon) → Adult (Moth). The larval stage is morphologically distinct from the adult stage, requiring a transformation process.
- Hen: Incorrect. Birds, including hens, undergo direct development. The chick that hatches from the egg resembles the adult bird and does not pass through a morphologically distinct larval stage.
Key Takeaway
Metamorphosis is characteristic of insects (like silkworms, butterflies) and amphibians (like frogs), where the young (larvae) look completely different from the adults. Mammals and birds typically undergo direct development.