Question

The common feature of all vertebrates is the presence of:

• A. limbs for locomotion
• B. a closed circulatory system
• C. a persistent notochord
• D. direct development into the adult stage after fertilization

Answer 1

The correct option is B a closed circulatory system

All vertebrates have a closed circulatory system wherein blood flows through closed blood vessels.
Limbs are absent in jawless vertebrates and Pisces. They have fins for locomotion.
Among the vertebrates, the notochord is present only in embryonic stages. It gets replaced by the vertebral column in adults.
In amphibians (vertebrates), the development is indirect. Indirect development refers to the development of an organism in which a larval stage is present. Direct development is the absence of a larval stage during the development of the embryo.