Class 7 Science Chapter 7 MCQ

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].

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.

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].

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

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].

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].

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.

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.

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].

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”.

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).