Class 7 Science Chapter 7 MCQ

Here, all the statements are correct. Hence, your answer will be option [D].

Water absorption through the roots can be increased by keeping the plants under the fan. As by keeping the plants under the fan, the transpiration process is boosted. Therefore, more amount of water and other minerals are absorbed by the plant roots from the soil. The more is the rate of evaporation of water from the plants the greater is the rate of transpiration. Hence, water absorption through roots can be increased by keeping the plants under the fan.

Plasma is a pale yellow, sticky liquid. Plasma is 90% water and 3.5% common salt.

Excretory system includes the tissues and organs related to the removal of waste products from the body. The removal of waste from the body system is called excretion. When the kidneys are failed to function properly, excessive amounts of fluid and toxic waste accumulate in the body. Dialysis is the treatment method in kidney failure patients which involves filtration and purification of the blood using a machine.

Anemia is a condition in which you lack enough healthy red blood cells to carry adequate oxygen to your body’s tissues.

White blood cells main chemicals known as antibodies to fight against infection.

In a tall tree, suction force is generated by continuous evaporation of water or transpiration, that pulls up water and minerals absorbed by the roots from the soil to reach the leaves.

Here, all the statements are correct. Hence, your answer will be option [D].

The “left ventricle” pumps oxygenated blood in to main artery for taking it to all the body organs, except lungs. The “right ventricle” pumps deoxygenated blood into pulmonary artery for taking it to lungs.

The heart is not a single pump. Actually, the heart is a double pump. The left side of heart and right side of heart act as two separate pumps.

Here, all the statements are correct. Hence, your answer will be option [D].

The left ventricle pumps blood into the aorta which in turn branches and delivers oxygenated blood to the major body regions and organs. The oxygen is consumed in cellular respiration and the carbon dioxide produced during respiration enters into blood. The anterior vena cava collects deoxygenated blood from the head, chest, and arms and enters the right atrium while the inferior vena cava collects blood from the lower body regions. Both vena- cava pass the deoxygenated blood to the right atrium. Thus, blood from tissues is rich in carbon dioxide. Deoxygenated blood from right atrium enters right ventricle and pulmonary arteries carry deoxygenated blood from right ventricle to lungs for oxygenation

Here, all the statements are correct. Hence, your answer will be option [D].

Veins have valves in them which allow the blood in them to flow in one direction which is only towards the heart.

The way in which waste product are excreted from the body of an animal depends on the availability of water to it. Aquatic animals live in water, so they excrete cell waste in gaseous form as ammonia which directly dissolves in water.

The top side of left atrium is connected to pulmonary vein which brings oxygenated blood into to heart from the lungs. The left ventricle pumps oxygenated blood in to main artery for taking it to all the body organs, except lungs. The top side of right atrium is connected to main vein called vena-cava, which brings deoxygenated blood into heart from all the body organs, except lungs. The right ventricle pumps deoxygenated blood into pulmonary artery for taking it to lungs. In the rhythmic contraction of heart where valves prevents the backflow of blood inside the heart during contraction.

Here, all the statements are correct. Hence, your answer will be option [D].

Veins normally carry deoxygenated blood or rich in carbon dioxide from the body organs. One vein that is “Pulmonary vein” carries oxygenated blood or rich in oxygen from the lungs to the heart.

A doctor listens to our heart beats with the help of an instrument called stethoscope.

Here, all the statements are correct. Hence, your answer will be option [D].

Sweat glands are absent in lips. These glands produce a liquid waste called sweat that contains water, salts and little urea. These are found over most of the body part.

Here, all the statements are correct. Hence, your answer will be option [D].

Veins normally carry deoxygenated blood or rich in carbon dioxide from the body organs. One vein that is “Pulmonary vein” carries oxygenated blood or rich in oxygen from the lungs to the heart.

The process of transpiration or evaporation of water, from leaves serves a very useful function in the plants because it generates a “suction force” in xylem which can pull water from the roots up to great height in the tall trees. Another function of transpiration is that it cools the plant in hot weather.

Capillaries are the extremely thin blood vessels where exchange of substances and absorption of nutrients takes place. Their thin walls facilitated the exchange. They connect arteries (carry oxygenated blood from the heart) to veins (carry deoxygenated blood from all the parts of the body to the heart).