Given below are a few common reflexes in humans. Classify them as a simple or conditioned reflex.

(i) Knee-jerk.

(ii) Watering of mouth on seeing a favourite dish.

(iii) Tying of shoe laces while talking.

(iv) Closing of eyelids if a strong beam of light is flashed across.

Given alongside is a partial diagrammatic representation of a certain phenomenon pertaining to the nervous system.

(i) Name the parts numbered 1-7

(ii) Name the phenomenon that the diagram depicts and define it.

(iii) Give the technical term for the point of contact between two nerve cells.

(iv) Name the parts not shown in the diagram that should be included to complete the pathway of the phenomenon.

Which of the following structures is absent in nerve cells ?

1. Nucleus
2. Cytoplasm
3. Centrosome
4. Neurilemma

The number of cranial and spinal nerves in a human being are respectively :

1. 31, 12 pairs
2. 32, 21 pairs
3. 12, 31 pairs
4. 31, 21 pairs