Question

Assertion : Osteichthyes fishes swim constantly to avoid sinking.
Reason : Air bladder is absent in fishes of Class Osteichthyes.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (D)

Members of Class Chondrichthyes are marine with streamlined body having cartilaginous endoskeleton. Due to the absence of air bladder, they have to swim constantly to avoid sinking. Air bladder is present in Osteicthyes which regulates buoyancy.