Final answer:
Flying is important for birds due to the advantages it provides. Structural modifications include adaptations in the skeletal system, respiratory system, and feathers.
Step-by-step explanation:
Flying is crucial for birds as it provides them with numerous advantages. Some of the structural modifications required for flight include adaptations in the skeletal system, respiratory system, and feathers.
Skeletal System: Birds have lightweight bones that are hollow and fused together. This reduces weight and allows for easier movement in the air.
Respiratory System: Birds have a unique respiratory system that includes air sacs for efficient oxygen exchange. This enables them to extract more oxygen from each breath, supporting their increased metabolic needs during flight.
Feathers: Feathers play a crucial role in flight by providing lift and generating thrust. The wings are made up of flight feathers that are strong, flexible, and have a streamlined shape to minimize air resistance.