Question

Choose the correct option-

A jawless fish, which lays eggs in freshwater and whose ammocoetes larvae after metamorphosis return to the ocean is?

• A. Petromyzon
• B. Neomyxine
• C. Myxine
• D. Eptatretus

Answer 1

The correct option is A

Petromyzon

The correct option is A

Explanation of correct option

1. Petromyzon marinus or sea lamprey is a jawless marine migratory fish that spends most of its adult life in the sea.
2. Matured fish migrate from marine to freshwater and lay eggs in areas with high oxygen levels.
3. These ammocoetes hatch and, before metamorphosis, migrate to the sea.

Explanation of incorrect option

Option B

Neomyxine biniplicata or hagfishes are non-migratory marine organisms without copulatory organs.

Option C

Myxine glutinosa or Atlantic hagfish are non-migratory marine organisms without copulatory organs.

Option D

Eptatretus stoutii or Pacific hagfish are non-migratory marine organisms without copulatory organs.

Final answer:

A jawless fish that lays eggs in freshwater and whose ammocoetes larvae after metamorphosis return to the ocean is Petromyzon.