Science 3 Marks Question

1. Trachea.
2. Ribs.
3. Diaphragm.
4. Stomata.
5. Spiracles.
6. Lungs.
7. Nostrils.
8. Yeast.

1. Trachea
2. Ribs
3. Diaphragm
4. Stomata
5. Spiracles
6. Lungs
7. Nostrils
8. Yeast
9. Ant

1. Spiracles are present on the sides of insects’ body while stomata are present on the lower surface of leaves.
2. Spiracles are fewer in number as compared to stomata.
3. Spiracles lead to an extensive network of tracheal system which is absent in the leaves.

1. When sneezing, you should cover your nose so that the particles expelled by you would not be inhaled by others.
2. Yes.
3. No, it is process to remove/ clear the particles harmful for us resulting in clean, fresh air to enter the lungs.
4. Cleanliness and hygiene maintenance.

The process of taking in of air rich in oxygen into the body is called 'inhalation'. During inhalation, ribs move up and outwards and diaphragm moves down. This movement increases space in our chest cavity and air rushes into the lungs. Exhalation is the process of giving out of air giving out of air rich in carbon dioxide is known as 'exhalation'. During exhalation, ribs move down and inwards while, diaphragm moves up to its former position. This movement reduces the size of our chest cavity and air is pushed out.

Plant respires through the following ways:

1. Through stomata present in leaves.
2. Through lenticels present on the bark of stem.
3. Through root hairs which takes up air via spaces present between the soil particles.

An athlete needs to supply extra energy to his muscle cells which have worked hard during running. For this, he breathes faster and deeper so that more oxygen is supplied to the cells. This speeds up the breakdown of food and as a result, more energy is released.

Diaphragm and ribs help in breathing activity:

• During inhalation: Ribs move up and outwards and diaphragm moves down. This movement increases space in our chest cavity and air rushes into the lungs. The lungs get filled with air.
• During exhalation: Ribs move down and inwards, while diaphragm moves up to its former position. This reduces the size of the chest cavity and air is pushed out of the lungs.

• Both aerobic and anaerobic respiration are necessary for the survival of living organism.
• In both type of respiration, the food is broken and energy is released for the functioning of an organism.
• In both type of respiration, Carbon Dioxide, Water and Energy is produced finally.

1. Smoking is very injurious for the respiratory system. It harms lungs.

• It causes blockage in respiratory tract.
• It leads to lung cancer.
• It can cause disease like asthma and heart diseases.

2. Yes, smoking affects people who are passive smokers, i.e. those present nearby smokers.
3. Yes, the people should bot smoke in public areas as it can cause discomfort to others.

The values we understand are obedience, respect elders and healthy habits.

Pores present on the sides of insects are called spiracles, while pores present on the surface of leaves are called stomata. These structures are responsible for the exchange of gases with the atmosphere.

Differences between these two are as follows:

1. Spiracles are fewer in number as compared to stomata.
2. Spiracles lead to an extensive network of tracheal system, which is absent in the leaves.
3. Spiracles are present on the sides of insect’s body while stomata are present on the surface of leaves.

1. During emergency conditions (e.g. fatal accidents, lungs failure etc.), lungs do not work properly, artificial respiration is required.
2. The person gets oxygen though an instrument called ventilator which act as artificial lungs.
3. The person is kept on artificial respiration temporarily. When a person regains his health and starts breathing naturally, artificial respiration is no longer required.

Yawning is the action of opening one’s mouth wide while taking a long and deep breath of air. It is caused by insufficient oxygen in the body. It usually occurs when we are drowsy or sleepy because our breathing rate slows down during these situation. The lungs do not get enough oxygen from the air for respiration. Yawning helps in bringing more oxygen into the body through the wide open mouth.

Frog breathe by their moist skin and through lungs also. So, they do not have any, respiratory issue.
When frog enters into water, the skin of frog helps in respiration.
The oxygen rich air enters through the skin. When the frog is on land, a pair of lungs helps in respiration.
The lungs take the oxygen rich air through the nostrils from where the oxygen is absorbed by the blood and carried throughout the body.
The carbon dioxide from the blood is diffused back through the skin and lungs into the atmosphere.

Pores present on the sides of insects are called spiracles while pores present on the surface of leaves are called stomata. These structures are responsible for the exchange of gases with the atmosphere.
Differences between these two are as follows:

• Spiracles are fewer in number as compared to stomata.
• Spiracles lead to an extensive network of tracheal system which is absent in the leaves.

Paheli had cramps in her leg muscles after running. She felt pain in her legs because of accumulation of lactic acid in the leg muscles. Lactic acid is formed due to the anaerobic respiration in the muscle cells after heavy exercise or running. During heavy exercise, we require large amount of energy that is provided by muscle cells through anaerobic respiration (Oxygen present is used up for energy, so there is lack of oxygen). Due to the partial breakup of glucose lactic acid is formed. It gets accumulated in the muscle cells and causes pain and muscle cramps.

We often sneeze when we inhale a lot of dust-laden air to expel out these foreign particles. These particles get past the hair in the nasal cavity and irritate the lining of the cavity which results in sneezing.