Tail feathers in birds and caudal fin in the fish act as?
Rudder for changing the direction and speed
Explanation of correct option:
1. Option B:.Rudder for changing the direction and speed.
Both tail feathers and caudal fins in birds and fishes act as rudder which is for changing the direction and speed of movement.
Explanation for incorrect options:
2. Option A: Balancer to balance the body
● Birds have streamlined bodies to balance them during flight
● Fishes also have streamlined body shape where boat shaped body having tapering at both sides.
3. Option C: Stabilizer to stabilize the body at a specific height or depth.
● Lightweight body helps the birds to fly high.
● Air bladder in the fish makes them stabilize when goes down to deep water.
4. Option D: None of these
This is a wrong option because there is an option that is correct for the given question.
Final answer: Tail feathers in birds and caudal fin in the fish act as rudders for changing the direction and speed.