Why do lobsters molt their shells?

Answer: Growing requires new exoskeleton

Growing requires new exoskeleton ✓ — Correct! Lobsters have hard exoskeletons that don't grow. To get bigger, they must molt (shed the old shell) and grow a new, larger one. Before molting, they grow a soft shell underneath. They absorb water to swell up, crack the old shell, and crawl out. The new shell hardens over days. Lobsters molt 20-30 times to reach adult size!

Seasonal camouflage change — Wrong. Lobsters don't change color for camouflage seasonally. Molting is purely for growth, though some color changes can occur.

Removing parasites attached — Wrong. Molting does remove external parasites as a side benefit, but the primary reason is growth—the rigid shell prevents size increase.