Class 7 Science Chapter 7 MCQ

The vascular tissue called phloem, forms or two-way traffic in plants for transport of substances. It carries the food from leaves to the all-other parts of plant. The other options i.e., xylem tissue carries water from the roots of words to stem and leaves, vascular tissue consists of xylem and phloem vessels in plants and root hairs absorb water from the soil that moves from cell to cell in the root and ultimately enters the xylem vessels.

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.

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

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.

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

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

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.

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.

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

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

The arteries lie quite deep under our skin and hence they are not seen easily. The veins are less deep than arteries and hence can be seen easily.

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.

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

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

The arteries have thick and elastic walls because blood flows through them at high pressure. The thick and elastic walls of arteries can withstand the high pressure of blood flowing through them. Veins have valves in them which allow the blood in them to flow in one direction only that is towards the heart.

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

Each kidney contains thousands of tiny filters called nephrons.

Urine contains 88 % of excreted nitrogen (N), 67 % of excreted phosphorous (P) and 73% of excreted potassium (K),“the remainder is in the faeces”. An adult excretes on average 500 liters (0.8-1.5 L per day in 4-5 times) of urine and 50 liters of faeces per year. Children urinates about half of the adult’s amount.

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 excretory system of human beings consists of the following organs as two kidneys, two ureters, a bladder and a urethra. Every person has two kidneys. The function of kidney is to filter the blood to remove urea. Each kidney contains thousands of tiny filters called “Nephron”.

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).