Answer: Option A. ->  Sensory nerves
:
A
The pain message is sent to our brain through the sensory nerves.These nerves carry impulses from the sense organs to either the spinal cord or the brain. Motor nerves carry impulses from the brain and spinal cord to the muscle and glands. Cerebellum and cerebrum are parts of the human brain.

Answer: Option C. -> Diabetes 
:
C
Diabetes iscaused by a deficiency of the pancreatic hormone insulin, which results in a failure to metabolize sugars and starch. Sugars accumulate in the blood and urine since they are not used by the cells due to lack of insulin.

Answer: Option C. -> Blinking of eyes
:
C
Blinking of eyes is not a reflex action, but it is involuntaryaction. Areflex action is one which occurs spontaneously whereas involuntary action happens without the conscious choice of an organism. The way the iris in our eye adjusts the size of the pupil in response to sudden bright or dim light is a reflex action. But blinking of eyes is an involuntary action.

Answer: Option C. -> pituitary gland
:
C
The pituitary gland is a pea-sized structure located at the base of the brain, just below the hypothalamus, to which it is attached via nerve fibers. One of the main hormones produced by pituitary is the growth hormone. This hormone is responsible for growth of the body.

Answer: Option A. -> True
:
A
Ethylene is a gaseous plant hormone released outside the plant body, unlike other hormones which are released inside the plant body. This gaseous hormone induces the ripening of fruits.

Answer: Option A. -> Touching the hot pan
:
A
In the given case, touching the hot pan is the stimulus and pulling the hand back is the response.

Answer: Option C. -> 1-ii, 2-i, 3-iii
:
C
The rearranged words are as follows:
1. DWARFISM
2. OESTROGEN
3. THYROXINE

• Dwarfism is a condition that occurs as a result of deficiency of growth hormone in childhood.


• Oestrogen is the hormone secreted in females at puberty. Oestrogen plays a role in the development of so-called female secondary sex characteristics, such as breasts, wider hips, pubic hair and armpit hair.


• Thyroxine is the hormone which regulates carbohydrate, protein and fat metabolism in the body.It plays a crucial role in heart and digestive function, metabolism, brain development, bone healthand muscle control.

Answer: Option B. -> At the shady side of the shoot.
:
B
When growing plants detect light, a hormone called auxin, synthesised at the shoot tip, help the cells to grow longer. When light is coming from one side of the plant, auxin diffuses towards the shady side of the shoot. This concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light. Thus, the plant appears to bend towards light.

Answer: Option C. -> Nerve impulse
:
C
$\bullet$ Nerve impulses are simply signals that are transmitted along nerve fibres (or neurons). It is the process by which neurons communicate with one another.
$\bullet$ The transmission of a nerve impulse along a neuron from one end to the other occurs as a result of difference in electrical charges across the membrane of the neuron.
$\bullet$ Nerve impulses can travel very quickly because they are electrical impulses.

Answer: Option A. -> Reflex arc, A - Receptor, B - Sensory neuron, C - Motor neuron, D - Relay neuron
:
A
The figure shown above represents the pathway of the impulse taken during a reflex action. The pathway is called reflex arc. The components of a reflex arc are:
A: Receptor: The receptor acts as a sensory organ and detects the external stimulus.
B: Sensory neuron: It takes the information detected by the receptor to the spinal cord. The spinal cord processes this information and gives a signal.
C: Motor neuron: It takes the signal from spinal cord to the effector organ.
D: Relay neuron: It connects the sensory neuron to the motor neuron.
The effector organ, in this case a muscle, does the action of pulling the hand away from hot pan.