The region of the vertebrate eye where the optic nerve passes out the retina, is called the –(a) fovea(b) iris(c) blind spot(d) optic chiasma.

8 Explain the following:(a) Role of Na⁺ in the generation of action potential.(b) Role of Ca⁺⁺ in the release of neurotransmitters at a synapse.(c) Mechanism of generation of light induced impulse in the retina.(d) Mechanism through which a sound produces a nerve impulse in the inner ear. 9 Differentiate between(a) Myelinated and Non Myelinated axons(b) Dendrites and axons(c) Rods and cones(d) Thalamus and hypothalamus(e) Cerebrum and cerebellum. 10 Answer the following(a) Which part of the ear determines the pitch of a sound?(b) Which part of the human brain is the most developed?(c) Which part of our central neural system acts as a master clock? 12 Distinguish between – (a) Afferent neurons and efferent neurons (b) Impulse conduction in a myelinated nerve fibre and unmyelinated nerve fibre (c) Aqueous humor and vitreous humor (d) Blind spot and yellow spot.  Cranial nerves and spinal nerves.