Science 3 Marks Question

Transpiration is the evaporation of water from the plants. The water evaporates through the stomata present on the surface of the leaves.

Transpiration is mainly responsible for the loss of water that was absorbed by the plants. However, it is important for plants as it helps in the movement of water to the top of tall trees. As a result, it helps in the distribution of water throughout the plant body. It also helps in cooling the plant.

Transport of materials is necessary in both plants and animals as every cell needs a regular supply of nutrients and oxygen for releasing energy through respiration. The food that we eat is broken down into smaller components to be absorbed by the cells. The oxygen that we inhale is also transported to all the cells of the body. Our body also requires a constant removal of waste materials such as carbon dioxide. For the transport of all these materials (food, oxygen, and wastes), our body has a specialised transport system. Similarly, in plants, the transport of water and food is accomplished with the help of a complex transport system.

1. A wound stops bleeding after sometime due to the process of clot formation. It plugs the cut and bleeding stops.
2. Wounded area becomes dark red in colour due to the clotting of blood.
3. The blood clot is formed due to the presence of the cells called platelets in the blood.

In human, the heart has four chambers. The two upper chambers are called the atria and the two lower chambers are called the ventricles.
On the left side are the left atrium and left ventricle and on the right side of the heart are right atrium and right ventricle.
The left side of the heart is completely separated from its right side by means for a partition of thick muscles called the septum. This septum prevents the mixing of oxygenated blood on the left side with the deoxygenated blood on its right side.

Stomata are tiny pores present on the surface of a leaf. Functions of stomata:

1. Stomata help in the exchange of gases.
2. Evaporation of water from the leaf surface occurs through stomata.

Transport of materials is very important in plant or in animals as all organisms need food, nutrition, water and oxygen for survival. The food is the source of energy and every cell of an organism gets energy by the breakdown of glucose. The cells use this energy to carry out vital activities of life. Therefore food must be made available to every cell of an organism. They need to transport all these to various parts of their body. Further, animals need to transport wastes to parts from where they can be removed.

1. Bleeding stops after sometime because some specialised cells start forming a hard covering called clot at the site of wound.
2. Bleeding is a fluid connective tissue present in all parts of the body. Platelets are responsible for formation of clot.
3. Mansi is helpful, knowledgeable and interested in science subject.

1. Arteries: Carry blood from heart to different parts of body.
2. Veins: Carry blood from different parts of body to the heart.
3. Capillaries: Exchange of material between blood and surrounding cells.

The correct order of the formation and removal of urine in human beings is:

4. Blood containing useful and harmful substances reaches the kidneys for filtration.

5. Useful substances are absorbed back into the blood.

2. Wastes dissolved in water is filtered out as urine in the kidneys.

1. Ureters carry urine to the urinary bladder.

3. Urine stored in urinary bladder is passed out through the urinary opening at the end of the urethra.

If there are no platelets in the blood, then the blood would not be able to clot. A clot is formed because of platelets. They release blood clotting chemicals at the site of injury. These chemicals form a clot and prevent further bleeding.

After the few hours, the figure will be shown as follows, This figure shows that there will be an increase in the level of sugar solution in the potato piece. This increase in the level of sugar solution rises due to water that passes through the wall of potato and goes inside it.

Some animals that surround us are fish, frog, birds, tadpole larva, snake, cow, man, rat, monkey, lizard, toad and snail.These can be grouped as follows:

1. Animals that excrete ammonia in gaseous form (i.e. ammonotelics)- Fish, tadpole larva.
2. Animals that excrete uric acid in the form of pellets (i.e. uricotelics)- Bird, snake, rat, lizard, snail.
3. Animals that excrete urea in the form of urine (i.e. ureotelics)- Frog, cow, man, monkey, toad.

After a few hours, the same set-up would be as shown as below:

This figure shows that there will be an increase in the level of sugar solution in the potato piece. The level of sugar solution can rise only if some water from the petridish passes through the wall of potato and goes inside it.
Since, the water level has risen, it shows that water can move from cell to cell in the potato wall and reaches inside the cavity.

The heart is an organ which beats continuously as a pump for the transport of blood carrying other substances with it, through a network of tubes or blood vessels. The heart pumps blood throughout our life without stopping or relaxing.

• It transports substances like digested food from the small intestine to the other parts.
• It carries oxygen and carbon dioxide to their respective organs and tissues.
• It transports wastes for removal from the body.

S. No.	Arteries	Veins
(i)	They carry oxygenated blood from heart to different organs.	They carry deoxygenated blood from the organs to the heart.
(ii)	They are usually deep-seated.	They are superficial in position.
(iii)	They do not contain valves.	They contain valves at regular intervals.

All cells of our body produce waste products. These waste products are toxic to the body and therefore need to be excreted out. This process of removing waste products produced in the cells of living organisms is called excretion.

The main function of artery is to carry blood away from the heart. Also, arteries have thick walls and do not contain valves. Blood flow in arteries, takes place at high pressure. All these characteristics are found in pulmonary artery. It carries away deoxygenated blood from heart to lungs for oxygenation, therefore it is called an artery.

Possible answers are:

1. Without the root hairs, the roots will not be able to absorb water and nutrients and the plant will die.
2. The stem of the rose plant may grow new roots and the plant will live.
3. The rose plant may not be able to survive in a different type of soil.

1. The name of the given instrument is stethoscope. It is a device used to amplify the sound of the heart. It consists of a chest piece that carries a sensitive diaphragm, two ear pieces and a tube joining the parts.
2. Labelled diagram of stethoscope.

• Take a potted plant.
• Cover it by polythene so that its roots along with soil get completely covered. This will prevent evaporation of water from the soil.
• Put a bell jar over the potted plant.
• Apply vaseline on the rim of the jar, this will prevent air from entering the jar from outside.
• Keep this set-up in the sunlight for some time.
• You will find drops of water on the inner side of the bell jar. These drops are due to the process of transpiration.

The circulatory system is made up of the Blood vessels, heart and Blood that help and control the flow of the blood around the body. Heart pumps blood around your body by alternate systole and diastole. Blood is the connective tissue that carries food, air, waste product and hormones. it contain fluid medium called plasma and three types of cell RBC,WBC and Platelets. There are three distinct types of blood vessels, namely, arteries, veins and capillaries circulate blood around body.