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Chapter 7

Disease and Hygiene

Class 6 - Concise Biology Selina

Multiple Choice Questions

Question 1

Malaria is caused by

  1. Bacteria
  2. Protozoan
  3. Fungi
  4. virus



Reason — Malaria is caused by protozoan Plasmodium which enters the human body through the bite of a female Anopheles mosquito.

Question 2

Deficiency of calcium causes

  1. Poor growth of teeth and gums
  2. Goitre
  3. Anaemia
  4. Polio


Poor growth of teeth and gums

Reason — Deficiency of calcium leads to poor growth of teeth and gums and brittle bones.

Question 3

Hay fever and asthma are

  1. Deficiency diseases
  2. Genetic diseases
  3. Organic diseases
  4. Allergic diseases


Allergic diseases

Reason — Hay fever and asthma are Allergic disease because both disease are caused by unpredictable reaction of the body to a particular substance.

Question 4

Infectious diseases can be prevented by

  1. Medicines
  2. Proper food
  3. Immunisation
  4. Exercise



Reason — Immunisation stimulates the body to produce antibodies that fight infection. In this way immunisation gives protection against infectious diseases.

Question 5

Which one of the following is a genetic disease?

  1. Scurvy
  2. Leukemia
  3. Goitre
  4. Haemophilia



Reason — Haemophilia is a genetic disease because it is inherited from parent to child.

Question 6

Which one of the following is a degenerative disease?

  1. Thalassemia
  2. Beri-beri
  3. Cataract
  4. Diabetes



Reason — Cataract is a degenerative disease because it is a age related eye disease which affects older person.

Question 7

Pellagra is caused by the deficiency of

  1. Vit. B3
  2. Vit. B1
  3. Vit. C
  4. Vit. D


Vit. B3

Reason — Pellagra is caused by the deficiency of Vit. B3 (Niacin).

Question 8

Deficiency of Iodine in one's food can cause

  1. Beri-beri
  2. Goitre
  3. Scurvy
  4. Pellagra



Reason — Deficiency of Iodine causes Goitre.

Question 9

Which one of the following mineral deficiency diseases can be cured by eating a diet which includes green leafy vegetables, banana, cereals, egg yolk?

  1. Goitre
  2. Anaemia
  3. Brittle bones
  4. Pain in muscles contraction



Reason — Anaemia is a iron deficiency disease which is an important component of haemoglobin. The deficiency of iron can be compensated only by consuming green leafy vegetables, banana, cereals, egg yolk.

Question 10

Which one of the following vitamin deficiency disease can be cured by eating a diet which includes carrot, yellow fruits, vegetables, butter milk,fish?

  1. Beri-beri
  2. Dermatitis
  3. Night blindness
  4. Scurvy


Night blindness

Reason — Night blindness is caused by deficiency of Vitamin A. Sources of Vitamin A are carrot, yellow fruits, vegetables, butter, milk, fish.

Question 11

Which one of the following is a communicable disease?

  1. Measles
  2. Cancer
  3. Heart stroke
  4. Allergy



Reason — Measles is a communicable disease because it is spread by direct contact with an infected person.

Short Answer Questions

Question 1(a)

What is a non-communicable disease?


The diseases which are caused either due to improper functioning of the body organs or due to the deficiency of certain minerals and vitamins in the body are known as non-communicable diseases. These diseases are not caused by any germ, therefore these diseases cannot spread from one person to another (i.e., they are non-transmissible). Examples — rickets, diabetes, heart diseases, etc.

Question 1(b)

What is a deficiency disease?


A disease which is caused due to the deficiency of certain nutrients, vitamins and minerals in the diet is called a deficiency disease. Example - Anaemia, Goitre.

Question 1(c)

What are communicable diseases?


The diseases that can easily spread from an infected person to a healthy person through disease causing germs called pathogens are called communicable diseases.

Question 1(d)

Biting nails should be strictly avoided. Give reason.


Dirt and many disease causing pathogens get accumulated under the nails. It is difficult to remove them even if we wash our hands frequently. Biting nails may cause these pathogens to enter into our body through our mouth causing various diseases. Hence, biting nails should be strictly avoided.

Question 1(e)

Regular exercise and proper rest is a must. Give reason.


Regular exercise keeps the body muscles active. It helps in the normal functioning of the heart and lungs and also in better circulation of blood. Proper rest helps the body repair, regenerate and recover.

Question 1(f)

Children eating more fast foods tend to suffer from obesity (overweight). Comment.


Fast foods are rich in fats and carbohydrates and deficient in vitamins. Eating more fast foods results in the accumulation of fat in the body of children making them suffer from obesity.

Question 1(g)

How can you control the spreading of diseases by mosquitoes and houseflies?


We can control spreading of diseases by mosquitoes and houseflies by using repellents, throwing garbage in covered bins, avoiding stagnation of water and covering all the drains prevent breeding of mosquitoes.

Question 1(h)

Public hygiene is equally important as personal hygiene. Give reasons.


Maintaining public hygiene prevents the spread of communicable diseases like Malaria, Dengue, Cholera, Diarrhoea, etc. Maintaining a clean environment controls the breeding of mosquitoes, houseflies and other pathogens. Hence, public hygiene is equally important as personal hygiene for good health and preventing diseases.

Question 2

Name the following:

(a) A bacterial disease caused due to contaminated water.

(b) A disease caused due to Plasmodium.

(c) A disease caused due to the bite of female Culex mosquito.

(d) A viral disease spread by the bite of a dog.

(e) Two diseases caused due to the deficiency of protein in the diet of a child.

(f) Any three water-borne disease.


(a) Cholera

(b) Malaria

(c) Elephantiasis

(d) Rabies/Hydrophobia

(e) Kwashiorkor and Marasmus

(f) Typhoid, Cholera, Jaundice

Question 3

Write short notes (1-2 sentences) on each of the following:

  1. Disease

  2. Pathogen

  3. Allergy


  1. Disease — Any physical or functional change in the body from a normal state which causes discomfort or disability is called a disease. Disease is a departure from normal health through structural or functional disorder of the body.

  2. Pathogen — Micro-organisms which cause communicable diseases are called pathogens. These germs are transmitted through various agencies like air, insect bites, rodent, contaminated food or water, etc. Pathogens may be different kinds of bacteria, viruses, fungi, protozoa or worms.

  3. Allergy — Allergy is an unpredictable reaction of the body to a particular substance called allergen. A few common allergens are dust, spores, pollens, certain clothes, particular medicines, cosmetics, etc. Asthma, Eczema, Diarrhoea, Vomiting, Nausea, etc. are some of the common allergic reactions.

Question 4

Fill in the blanks by selecting suitable words given below:

(goitre, insulin, rickets, iron, proteins)

(a) Anaemia is caused due to the deficiency of ...............

(b) Deficiency of Vit.D causes ............... in children.

(c) Deficiency of iodine in the diet may cause ...............

(d) Kwashiorkor is caused due to the deficiency of ...............


(a) Iron

(b) Rickets

(c) Goitre

(d) Proteins

Question 5

Find the odd one out:

(a) Typhoid, cholera, jaundice, tuberculosis, tetanus.

(b) Cold, malaria, measles, mumps.

(c) Scurvy, rickets, polio, pellagra, night blindness.

(d) Proteins, carbohydrates, fats, minerals, cancer.


(a) Jaundice
Reason — Jaundice is not caused by bacteria while others are bacterial diseases.

(b) Malaria
Reason — Malaria is caused by a protozoan while others are viral diseases.

(c) Polio
Reason — Polio is a viral disease while others are vitamin deficiency diseases.

(d) Cancer
Reason — Cancer is a disease while others are food components.

Question 6

Fill in the blanks in the following table:

VitaminName of the
deficiency diseases
source of vitamin
(a) Vitamin A..............................
(b) ...............Beri-beri...............
(c) Ascorbic acid..............................
(d) ...............Rickets (in childhood)
bones turn soft


VitaminName of the
deficiency diseases
source of vitamin
(a) Vitamin ANightblindness, drying of corneaCarrot, yellow fruits, vegetables, butter, fish, milk.
(b) Vitamin B1Beri-beriWhole grains, eggs, nuts, legumes, yeast.
(c) Ascorbic acidScurvy
(bleeding gums)
Citrus fruits, tomatoes, germinating seeds.
(d) Vitamin DRickets (in childhood)
bones turn soft
Egg yolk, fish liver oil, sunlight, milk, butter.

Long Answer Questions

Question 1

Describe the ways in which communicable diseases are transmitted through various indirect methods.


Indirect method of transmission of communicable disease are:

  1. From items used by the infected person — Touching and sharing items like towels, handkerchiefs, combs, utensils, etc. of an infected person may spread the disease to a healthy person.
  2. Contaminated food and water — Houseflies carry germs from garbage and sewage and deposit them on food. Contamination of drinking water even with little amount of faeces or dung can cause a number of diseases.
  3. Droplets through air — The droplets coming out when a person infected with common cold, TB, etc. sneezes or coughs, transmit the disease causing germs through the air spreading the disease to more people.
  4. Vectors or carriers — Houseflies, mosquitoes, rodents, etc. also carry disease causing germs.

Question 2

List 3 ways by which you should keep your environment clean.


Three ways to keep the environment clean are:

  1. Maintain a clean environment to prevent the spreading of diseases due to the breeding of mosquitoes, houseflies and pathogens.
  2. Garbage should be kept in covered bins so that flies do not breed on it.
  3. There should be proper sewer lines connected to sewage treatment plants.