Question

Which one is correctly matched?
A. Tibia and fibula – Both form part of the knee joint
B. Cartilage and Cornea – No blood supply but do require \[{O_2}\] for respiratory needs
C. Shoulder joint and elbow joint – Ball and socket joint
D. Premolars and molar – 20 in all and 3-rooted

Answer 1

Hint: The knee joint is found in the knee region. The cartilage is a soft structure found in the ear pinna, nose tip, etc. The cornea is found in the eyes. The shoulder joint and the elbow joints are both found in the hand. The premolars and the molar are the types of teeth found in the human mouth.

Complete answer:
a) The first pair is tibia and fibula – Both form the part of the knee joint. The tibia and the fibula are bones of hind limbs or the legs. These bones are present in the shank region. The knee joint is formed by the articulation of bones of the patella, femur and tibia.
b) The second pair is the cartilage and cornea – Here, no blood supply can be seen, but they do require \[{O_2}\] for respiratory needs. The cartilage is a supporting type of connective tissue. It is softer than bones. They are formed by chondrocyte cells. Cartilage is made up of calcium carbonate. Whereas, the cornea is a dome-shaped, transparent structure present in the sclera of the eyes. Both the cartilage and the cornea do not have any blood supply. However, these organs require oxygen for respiratory needs.
c) The third pair is the shoulder joint and elbow joint – Ball and socket joint: The elbow joint both has a hinge joint. The hinge joint allows movement in only one direction or one plane. The ball and socket joint is a type of free joint allowing movement in all the planes. It is found in the shoulder joint.
d) The fourth pair are premolars and molars – 20 in all and 3-rooted: Premolars are bicuspid teeth used for chewing. The molars are the tricuspid teeth used for grinding. There are eight premolars and twelve molars. The premolars are two-rooted. Only molars are three-rooted.
Hence, the correct answer is option B.

Note: The main function of the cornea is to regulate light rays entering the eye to the interior portion. It bends the light rays so that they can be brought to a focus. The tear glands secrete various secretions to keep the surface of the cornea moist and dust-free.