question_answer 11)

What are the modifications that are observed in birds ' that help them fly?

Answer:

Flight adaptations in birds (i) Boat-shaped body helps to propel through the air easily. (ii) Feathery covering of body to reduce the friction of air. (iii) Holding the twigs automatically by hindlimbs. (iv) Extremely powerful muscles that enables the wings to work during flight.    (v) Bones are light, hollow and provide more space for muscle attachment. Presence of pneumatic bones which reduce the weight of body and help in flight.                               (vi) The first four thoracic vertebrae are fused to form a furculum for walking of the wings.       (vii) Lungs are solid and elastic and have associated air sacs.         (viii) The power of accommodation of eyes is well developed due to the presence of comb-like structure pecten. (ix) A single left ovary and oviduct to reduce the body weight.