Which one of the following pairs of types of teeth perform one common function as stated against it?

1. Incisors, canines — Holding
2. Canines, premolars — Tearing
3. Premolars, molars — Grinding
4. Molars, incisors — Tearing

The hardest substance in the human body is :

1. Bone
2. Enamel
3. Cement
4. Dentine

The temperature range within which enzymes can act best is :

1. 20° to 30°C
2. 35° to 40°C
3. 40° to 45°C
4. 35° to 50°C

Heterodont dentition is found in :

1. Humans
2. Snake
3. Frog
4. Lizards