Solution to Extended Learning – Activities and Projects Question 2 of NCERT Class 7 Science Chapter 6 Respiration in Organisms

2. Visit a local doctor. Learn about the harmful effects of smoking. You can also collect material on this topic from other sources. You can seek help of your teacher or parents. Find out the percentage of people of your area who smoke. If you have a smoker in your family, confront him with the material that you have collected.

Answer: The harmful effects of smoking should not be underestimated and are as follows:

(i) Cancer: Smoking can cause cancer in any part of your body including your mouth and jaw (buccal cavity), oesophagus, lungs, stomach, pancreas etc. The majority of lung cancer deaths are said to be caused by smoking. Below is a graphic of the damage smoking can cause to your lungs, which may even lead to lung cancer:

Blackened smoker's lungs caused by smoking.
Smoker’s Lungs: Smoking damages your lungs and leads to many diseases.

(ii) Heart Attack and Stroke: Smoking causes deposition of plaque which narrows the gap of the arteries and restricts the flow of blood in the arteries. Smoking also causes blood clots inside arteries and veins. Both of these block the passage of blood and oxygen to vital organs like the heart and the brain. This greatly increases the risk of heart attack and stroke.

Smoking nearly doubles the risk of heart related diseases and stroke over a person’s lifetime. More than 1 in 2 smoking adults are known to develop heart disease. Around one-fourth of all strokes are a result of excessive smoking.

Clogged arteries due to smoking.
Clogged Arteries: Smoking results in deposition of plaque inside arteries, which results in narrowing.
Blood clots due to smoking.
Blood Clots: Smoking causes blood clots, which block the flow of blood.

(iii) Emphysema: Over time, due to excessive smoking, the air sacs or alveoli in the lungs get damaged. Impurities resulting from smoking get trapped in the alveoli and eventually destroy them. Emphysema is chronic and its harmful effects cannot be reversed.

Alveoli in the lungs destroyed by emphysema.
Emphysema: Deposits due to smoking get trapped in and destroy the alveoli in the lungs.

(iv) Respiratory Diseases: Smoking narrows the airways through which air passes back and forth between the lungs and increases the risk of many respiratory diseases such as bronchitis, asthma etc and even common cold.

(v) Other Health Conditions: Chronic diseases like diabetes, loss of vision are caused by diabetes. Also, it makes the body unfit and destroys the body’s immune system, making it much more susceptible to many kinds of infections.

(vi) Second hand Smoke: Second hand smoke is the smoke you inhale that someone else has just breathed out. This second hand smoke that you inhale can in many cases be just as harmful as when you smoke yourself. It is best to avoid situations where you might be exposed to second hand smoke.

Child exposed to passive smoking.
Passive Smoking: Avoid passively inhaling secondhand smoke. Alert your friends and family.


In conclusion, excessive smoking can harm every single organ in your body, sometimes leading to multiple health problems at the same time. It is best to quit the smoking habit as early as possible and seek medical help and therapy.

If you collect information on the smoking habits of the people in your locality or neighbourhood, you can estimate the number of casual smokers (smoke infrequently), moderate smokers (smoke regularly), chain smokers (smoke excessively and are addicted). Here is sample data for an area in Delhi (the data will vary from place to place):

Percentage of smokers: 25%

Percentage of casual smokers: 6%

Percentage of moderate smokers: 12%

Percentage of chain smokers: 7%

Within the student’s family (including relatives), there were 2 teenage smokers and 5 adult smokers. The student showed them data from our website, warned them about the inevitable harmful effects of smoking and convinced them to quit smoking and seek medical help if necessary. The child’s sincere appeal was taken to heart by all of them and they promised to exert discipline and self-control to let go of their smoking habits.


“Visit a local doctor. Learn about the harmful effects of smoking. You can also collect material on this topic from other sources. You can seek help of your teacher or parents. Find out the percentage of people of your area who smoke. If you have a smoker in your family, confront him with the material that you have collected.” – Solved.


Related Links:

Solution to Extended Learning Question 1
Solution to Extended Learning Question 3
Solution to Activity 6.1
Solution to Activity 6.2
Solution to Activity 6.3
Solution to Activity 6.4
Solution to Activity 6.5
Solution to Activity 6.6
Solution to Chapter 6 Respiration in Organisms

Scroll to Top


Free Demo Class!

CBSE Classes 6-10. First 50 students only!