Question

Which of the following is/are adaptations seen in birds that reduce their body weight for flight?

• A. Feathers
• B. Bones with air cavities
• C. Absence of urinary bladder
• D. Lungs with air sacs

Answer 1

Answer: (B), (C)

The correct options are
B Bones with air cavities
C Absence of urinary bladder

Birds have many adaptations to reduce their body weight. The bones are hollow and filled with air cavities. This makes the body light and aids in flying. Birds also consume much less amount of water and excrete solid urine which is formed of uric acid instead of urea which otherwise requires lots of water to be excreted out. They also lack urinary bladder. This makes their body light and helps them to take flight.