An obvious answer to this question by any layman will be “we cannot fly like birds because we do not have natural wings”. However this answer does not explain this question completely because even if we attach artificial wings to our arms we are still unable to fly. Then how do the birds fly?
Human beings cannot fly because they do not have a streamlined body
Birds have wings to assist them in flying. Apart from this they have very light frames and their bones are also light. Moreover they have air sacs which further reduce their body weight.
The muscles of birds are quite strong in comparison to their body weight. They have a streamlined body which enables them to fly swiftly because air offers less resistance to such objects. With the help of their strong muscles they can they can easily fly with their wings. But than we do not have any air sac and our muscles are not comparatively strong enough. Hence we cannot flap the artificial wings.
Birds having lighter bodies can fly more easily while heavy birds the cock face difficulties in flying for examples the cock and peacock cannot fly very high. There are also birds like ostrich and penguin which are even heavier. These birds cannot fly at all. They can merely run. Similarly we cannot fly like birds even if we attach artificial wings to our arms.
