Question

Calcified cartilage is present in
A. Pinna B
B. Supra scapula of the pectoral girdle of frog
C. Ends of bones
D. Intervertebral discs

Answer 1

Hint: Cartilages are flexible connective tissues made up of chondrocytes. These tissues often develop into bones by calcification in some animals. The suprascapular is a shoulder bone in frogs, which is a cartilage that acts as a bone as it is calcified.

Complete answer:
Cartilages are connective tissues that are flexible but provide structural support. It is made up of chondrocytes, collagen, connectin fibres, and several other fibrous and connective tissues. It can be found at the end of bones as they reduce friction between bones as they move. Several bone structures of many species are calcified cartilages.

As a young offspring, these structures are made up of cartilage, and as they age, the cartilage gets calcified and becomes more rigid so as to serve a better structural purpose. This process is known as calcification. In the case of a frog, the pectoral girdle consists of the cleithrum and the suprascapular. Suprascapular begins as a collection of chondrocytes during development. As the frog develops, the chondrocytes fuse and begin to calcify. The calcified structure then forms a rigid bone-like structure.

Therefore, the correct answer is option B.

Note: Calcification is a step in ossification and both terms should not be used interchangeably.
The pinna is the cartilage of the ear. This cartilage is not calcified as it remains flexible throughout the organism's lifetime. The intervertebral discs are cartilaginous structures. These structures under diseased conditions may have certain calcium deposits around the disc.