Cone cells of retina unable us to see the colours. There are three types of cones which possess their own characteristic photopigments that respond to red, green and blue light.

External Auditory canal $\rightarrow$ Eardrum $\rightarrow$ Malleus $\rightarrow$ The reception and transmis sion of sound wares occurs in following order-

Incus $\longrightarrow$ Stapes $\longrightarrow$ Cochlea $\longrightarrow$ Cochlear nerve

The following structures are involved in the protection of brain in animals

(i) Cranium There are 8 cranial bones which form the hard protective outer covering cranium for the brain.

(ii) Meninges The brain is covered with three membranes called meninges.

(a) Piamater Inner most membrane very thin, delicate and vascular and invests the brain closely.

(b) Arachnoid membrane It is like spider we in structure from which its gets its name.

(c) Duramater It is outer most, thick, tough fibrous membrane adhering closely to the inside of the skull.

(iii) Cerebrospinal fluid The cerebrospinal is present in the spaces between the meninges, i.e., arachnoid and duramater, which functions as a pad, absorbing shocks.

The inner part of cerebral hemispheres and a group of associated deep structures called limbic lobe or limbic system along with hypothalamus are involved in the above said functions, i.e., aggressive behaviour, use or abusive words, restlessness, etc.