Which of the following statements about fishes is correct?
Cartilaginous fishes (Chondrichthyes) lack an operculum and instead have gill slits for respiration. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Zoology section), Chapter: Human Physiology - Digestion, Respiration, Circulation, Neural Control and Chemical Coordination, Topic: Organ system functions and hormonal regulation.
