1. (d) Cytokinin.

2. (b) Synapse.

3. (d) All the above.

4. Receptors detect all the information from our environment. These receptors are
located in our sense organs.
In case any of the receptors do not work properly we will not be able to perceive that
particular information.

5. Neuron acquires particular information through dendrite located on its cell body.
This information is then passed on to the axon. Finally, axon ending passes the
information into next neuron at the synapse. As soon as the impulse reaches the
dendrite, an electrical impulse is generated due to certain chemical changes in
neuron. When the impulse reaches axon ending some chemicals released which pass
on the impulse to next neuron. These chemicals are known as neurotransmitters.

6. Movement of shoot towards light is called phototropism. This movement is caused
due to more growth of cells towards the shaded side of the shoot as compared to the
side of shoot towards light. More growth of cells is due to secretion of auxin towards
the shaded side.

7. (i) Reflex action
 (ii) Impulses from various body parts will not conducted to brain.
 (iii) Message from brain will not be conducted to various organs.

8. Chemical coordination in plants is maintained by plant hormones also known as
phytohormones. Some of these hormones promote growth while some inhibit it.
Some hormones include auxin, Gibberellins, Cytokinin etc.

9. An organism has different organs which perform various factions. The survival of an
organism depends on integrated and coordinated functions of these organs. Nervous
and endocrine system of an organism makes them work together like parts of one
machine to accomplish homeostasis or coordination.

10. Difference between involuntary and reflex actions is as follows:

It is a set of muscles movement over
which we do not have control. Such
actions are controlled by brain. For
example- contraction of muscle of our
digestive tract, beating of heart etc.
It is rapid, spontaneous and
involuntary activity that is produced in
response to a stimulus. It is controlled
by spinal cord. Example- removal of
hand with jerk when someone touches
a hot object.

11. Difference between nervous control and hormonal control:

Nervous Control
Harmonal Control
(i) Consists of nerve impulses
conducted by neurons from one organ
to another organ.
(ii) Nervous impulses produce rapid
short lasting responses.
(iii) Nervous impulses are not specific
in their action.
(i) It consists of endocrine system
which scretes chemical messengers
hormones secreted directly in blood.
(ii) Hormones produce longer lasting
(iii)Action of hormones is highly

12. Difference between movement in a sensitive plant and movement in our legs:

Movement in sensitive plants
Movements in our legs
(i) There is no specialized tissue in
plants for conduction of information.
(ii) Plant cells change shape by
changing the amount of water in them.
(iii) Plant cells do not have specialized
(i) There is specialized nervous tissue in
animals for conduction of information
and muscle cells to help in movement.
(ii) Muscle cells contract or relax to effect
(iii) Muscle cells have specialized protein
which help muscles to contract or relax.

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