Question

Why some birds can fly but some can not?​

Answer 1

Explanation:

The harder answer as why some birds might have evolved to not being able to fly. Ostriches, emus, cassowaries, rheas, and kiwis can't fly. Unlike most birds, their flat breastbones lack the keel that anchors the strong pectoral muscles required for flight.

Answer 2

Answer::

Some birds can fluly whereas others can't becuase the birds those who can fly have ; light hollow bones and light bodies,they have strong chest which helps them to flap their wings. But ,the birds who can't fly are heavy and don't have light and hollow bones which disables them from flying.