Question

In human, teeth are
A. Homodont and polyphyodont
B. Heterodont and polyphyodont
C. Homodant and diphyodont
D. Heterodont and diphyodont

Answer 1

Hint: Humans possess two sets of teeth during their life, i.e., one temporary set and one permanent set. The temporary set- milk or deciduous teeth are replaced by a set of permanent or adult teeth. Such type of dentition is known as diphyodont. Human dentition consists of 32 permanent teeth which are of four different types- incisors, canine, premolars, and molars. Such type of dentition is known as Heterodont dentition.

Complete answer:
> Homodont- Nonmammalian vertebrates are typically homodont, this means that all of their teeth are of the same shape, as seen in sharks and crocodiles.

> Heterodont- Mammals are typically heterodont, which means that they have a variety of tooth shapes. Most mammals possess incisors, canines, premolars, and molars. In anatomy, a heterodont refers to an animal that possesses more than a single tooth morphology. In vertebrates, heterodont relates to animals where teeth are differentiated into different forms. For example, members of the Synapsida.

> Polyphyodont- This refers to any animal whose teeth are continually replaced. They include most toothed fishes, many reptiles such as crocodiles and geckos, most other vertebrates and mammals being the main exception.

> Diphyodont- this refers to any animal with two successive sets of teeth, originally the "deciduous" set and successively the "permanent" set. Most mammals are diphyodonts—as to chew their food they need a strong, durable, and complete set of teeth.

Hence, the correct answer is option (D).

Note: Humans usually have 20 primary/ deciduous/ milk teeth and 32 permanent/ adult teeth. They are classified as incisors, canines, premolars (also called bicuspids), and molars. Incisors are mainly used for cutting, canines are for tearing, and molars serve for grinding.