Question

why bird can fly and why not human being?​

Answer 1

Answer:

the answer is simple

Explanation:

birds limbs have been modified into wings but not human

Answer 2

Answer:

A bird can fly because its wingspan and the wing muscle strength are in balance with its body size. It has a lightweight skeleton with hollow bones, which puts a smaller load on its wings. ... Thus, an average adult male human would need a wingspan of at least 6.7 meters to fly.