in Animals and Plants
Q38. What will happen if there are no platelets in the blood?
Platelets are tiny blood cells that help our body form clots to stop bleeding. When
we don't have enough platelets in our blood, our body cannot form clots and
bleeding won't stop which can be fatal.
Q39. Why is heart known as the pumping organ of the human body?
The heart is muscular organ which beats continuously to act as a pump for the transport
of blood, which carries other substances with it. Blood
provides the body with oxygen and nutrients, as well as assists in the removal
of metabolic wastes.
Q40. What is Dialysis?
Sometimes a person’s kidneys may stop working due to infection or injury. As a
result of kidney failure, waste products start accumulating in the blood. Such
persons cannot survive unless their blood is filtered periodically through an
artificial kidney. This process is called dialysis.
Q41. Why do veins have thin walls compared to arteries?
Arteries and veins experience differences in the pressure of blood flow. Arteries experience a pressure wave as blood
is pumped from the heart. This can be
felt as a "pulse." Because of this pressure the walls of arteries are
much thicker than those of veins.
Q42. What are the three main types of blood vessels?
There are three major types of blood vessels: the arteries, which carry the
blood away from the heart; the capillaries, which enable the actual exchange of
water and chemicals between the blood and the tissues; and the veins, which
carry blood from the capillaries back toward the heart.
Q43. How plant roots absorb water and minerals from the soil?
Plants absorb water and minerals by the roots. The roots have root hair. The
root hair increase the surface area of the root for the absorption of water and
mineral nutrients dissolved in water. The root hair is in contact with the
water present between the soil particles.
Q44. Why is transport of materials necessary in a plant or in an
All organisms need food, water and oxygen for survival. They need to transport
all these to various parts of their body. Further, they need to transport
wastes to parts from where they can be removed. Thus, transport of materials is
necessary in a plant or in an animal.
Q45. Why animals such as sponges and hydra do not have blood?
Animals such as sponges and hydra do not possess any circulatory system. The water
in which they live brings food and oxygen as it enters their bodies. The water
carries away waste materials and carbon dioxide as it moves out. Thus, these
animals do not need a circulatory fluid like the blood.
Q46. Does transpiration serve any useful function in the plants?
Ans. Plants absorb mineral nutrients and water from
the soil. Not all the water absorbed is utilised by the plant. The water
evaporates through the stomata present on the surface of the leaves by the
process of transpiration. The evaporation of water from leaves generates a
suction pull which can pull water to great heights in the tall trees.
Transpiration also cools the plant.
Q47. Why is blood needed by all the parts of a body?
What are the Functions of Blood in Human Body?
Blood is the fluid which flows in blood vessels. It transports substances like
digested food from the small intestine to the other parts of the body. It
carries oxygen from the lungs to the cells of the body. It also transports waste
for removal from the body. Thus blood is needed by all the parts of a body.
Q48. What are the three types of cells present in blood?
The three types of cells present in blood are:
Red blood cells (RBC) which contain a red
pigment called haemoglobin.
The blood also has white blood cells (WBC)
which fight against germs that may enter our body.
Platelets cells which helps in the clotting
of the blood.