Give scientific reason: Birds show adaptations for flight.

(N/A) $\rightarrow$ Forelimbs are modified into wings to facilitate flight.
$\rightarrow$ The body is streamlined,which reduces air resistance during flight.
$\rightarrow$ Bones are pneumatic (hollow and air-filled),which reduces body weight.
$\rightarrow$ Respiration occurs through lungs,which are supplemented by air sacs that provide extra buoyancy and efficient oxygen supply for high-energy flight.