Which advantages do feathers provide for birds?

a. Light insulation for heat conservation

b. Water-tight for water conservation

c. Volume for lift

d. Rigid structure to anchor strong muscles for flight

Answer: Option A.

Explanation:

Feathers are the epidermal growths which form the distinctive outer covering, or plumage of birds and several other vertebrates.

The major function of feather is to provide heat to the body which is possible by two ways light insulation (radiation) and conduction. In light insulation, feather of birds have the property of light scattering that allows to diffuse thermal radiation to keep the body of birds warm, results in heat conservation while in conduction, layer of air is trapped in the furs of feather which slowly heated the bodies of animals or birds.

Hence, the correct option is A.