Class Chondrichthyes - Practice Questions & MCQ

• This class contains the fishes with cartilaginous endoskeleton.
• Sharks, rays, skates, saw-fishes etc. belong to this class.
• The notochord persists throughout their life
• They have a tough skin covered with placoid scales.
• They have powerful jaws with modified placoid scales called the teeth. The mouth is ventrally located.
• The gill slits are not protected by an operculum.
• They do not have a swim bladder due to which they swim continuously to prevent sinking.
• They have a two-chambered heart with one atrium and one ventricle.
• They are cold-blooded.
• They have separate sexes. Fertilization occurs internally. They can be oviparous or viviparous.

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