Options:
A. They are muscles.
B. They are organs of unitary system.
C. They are technical names for blood groups.
D. They are bones.
✅ Correct Answer: D. They are bones.

Options:
A. They are muscles.
B. They are organs of unitary system.
C. They are technical names for blood groups.
D. They are bones.
✅ Correct Answer: D. They are bones.
