(a) Name the three types of nerves which constitute the peripheral nervous system.
(b)What is the difference between a reflex action and walking?
(c) How do we detect the smell of an incense stick (agarbatti)?

How do we detect the smell of an agarbatti (incense stick)?

Name the system which facilitates communication between central nervous system and the other parts of the body. Mention two types of nerves it consists of along with their organs of origin.

Indian Railway' is a part of Railway Ministry . It is organised and controlled by Railway Ministry . The finances are allocated from government treasury and what ever revenue it earns is deposited to government treasury only . It is treated as a part of government and even the appointment , recruitment and selection of employees is done in the same way as that of civil servant. (a) Name the type of public sector enterprise railway is considered as . (b) What is the status of employees working in railways? (c) How does it get its finance? (d) What does it do with its revenue?

(a) Name the part of brain which controls (i) voluntary action, (ii) involuntary action. (b) What is the significance of the peripheral nervous system? Name the components of this nervous system and distinguish between the origin of the two.

Examine the illustration of a portion of the deffective crystal and answer the following question : (a) What are these type of vacancy defects called ? (b) How is the density of a crystal affected by these defects ? (c) Name one ionic compound which can show this type of defect in the crystalline state. (d) How is the stoichiometry of the compound affected ?

(a) What is an atom ? How do atoms usually exist ? (b) What is a molecule? Explain with an example. (c ) What is the difference between the molecule of an element and the molecule of a compound ? Give one example of each.

When we touch a hot plane unknowingly then this heat is sensed by a receptor P present in oyr fingers. The receptor triggers an impulse in neuron Q which transmits the message to an organ R which is a part of the central nervous system. Here the impulse is passed on to a neuron S which in turn passes it to a yet another neuron T. The neuron T passes the impulse to a tissue U in our arm. The tissue U then contracts and pulls or hand away from the hot plate. (a) What is the name of (i) receptor P (ii) neuron Q, and (iii) organ R? (b) What is (i) neuron S, and (ii) neuron T? (c) Name the tissue U. (d) What name is given to the phenomeon in which hand is pulled quickly from the hot plate? (e) Name the effector in this whole process.