MAHARASHTRA STATE BOARD SCIENCE

2. Fill in the blanks:
•The loss of water from the plants is known as
_____________. (Transpiration)
•Nervous system is absent in _______ and
____________. (plants, unicellular organism)
•Response to the stimulus of touch is called
__________ whereas response to the stimulus
of chemicals is called as _____________.
(eismonastic movement, chemotropism)
•Brain is the main ____________ centre of the
body. (coordinating)

3. Name the following:•Growth of plant in response to external factors.
Ans. Tropism
•Maintenance of steady state by different system in an
organism.
Ans. Homoeostasis
•Cells that assist the neurons in their function.
Ans. Neuralgia
•The small gap between the consecutive neurons.
Ans. Synapse
•Part of the brain that co – ordinates the voluntary
movements.
Ans. Cerebellum
•Name the sense organs.
Ans. Eyes, ears, nose, tongue and skin are the five
sense organs

4. •Roots of plants grow away from
light.
•The root system of plants always
grows downwards in response to
the stimulus of gravity and water.
•This makes sure that the roots will
find soil and water.
Hence, the roots of plants grow
away from light

5. Hormones secreted by the endocrine glands
are present everywhere in the body.
•Endocrine glands do not have ducts to store or
transport their secretions called hormones.
•The hormones are directly released into the
blood stream and reach concerned body parts
through blood.
Hence, hormones secreted by the
endocrine glands are present everywhere in
the body

6. •Insulin plays an important role in
controlling the sugar level of blood.
•When the sugar level of the blood rises, it
is detected by the cells of the pancreas
which respond to the situation by
producing more insulin.
•As the sugar level of the blood falls, the
secretion of insulin is reduced.
Thus, insulin plays an important role in
controlling the sugar level of blood.

7. •Explain the following terms:
1.Hydrotropic
movement:
The
movement or growth of the root system
of a plant in response to the stimulus of
water is called hydrotropic movement.
2.Chemical control in animals: chemical
control in animals is brought about by
chemical substances called hormones.
These hormones are secreted by the
endocrine glands.

8. Voluntary movements
Involuntary movements
i. Voluntary movements are i. Involuntary movements are
according to our own will.
not according to out own
ii. Voluntary movements are will.
caused by motor region of ii. Involuntary movements are
cerebrum but are controlled caused by medulla oblagata
by cerebellum.
and some part of midbrain.
iii.They are under the control iii.They are under the control
of central and peripheral of
autonomic
nervous
nervous system.
system.

9. 1.Reflex action
•The sudden action in response to some happenings in the
environment is called as reflex action.
•It is an involuntary action which we perform automatically.
•The path way taken by nerve impulses in a reflex action is
called reflex arcs. Reflex arcs allow rapid response.
•A nerve from all over the body meet in a bundle in such a
connection is commonly called as the spinal cord, before
impulses are sent to the brain.
•Hence, reflex arcs are formed in the spinal cord, although
the messages reach the brain.
Pulling away our hand on touching a hot object,
narrowing of the eyes in sunlight, watering of the mouth
on smelling something delicious etc. are examples of
reflex action.

10. Co – ordination in plants.
a.Plants do not have a nervous system or muscular
system and sense organs like eyes, ears, nose, etc.
b.The plants can still sense the presence of stimuli like
touch, light, gravity, water, etc., and respond to them
by the action of hormones in them.
c.So, plants co – ordinate their behaviors against
environmental changes by using hormones.
d.Hormones bring about various movement in
response to stimulus.
e.It is the result of such co – ordination that the lotus
opens in the morning and the tube rose at night; stem
grow towards light and the root towards gravity; the
leaflets of the mimosa plant close on being touched
and the explosive fruit of balsam burst open to scatter
the seeds.