Class 9 Science
Chapter 13 Why do we fall ill
Q- 1 What is the meaning of being healthy?
Ans – Health is state of being well enough to function well physically, mentally and socially. Being physically well means a person with no major disease or being disease free. Being mentally well means a person who is fit mentally. Being Socially well means our social environment should be healthy.
Q- 2 What is a disease?
Ans – Disease means disturbed ease or being uncomfortable. Disease is a situation in which a person experiences some specific symptoms and causes for the discomfort.
Q- 3 What is meant by the symptoms of a disease?
Ans – When a person experiences some special situations for a particular cause which has happened in the body then these are the symptoms of a particular disease. For example – headache, loose motions, body pain, fever or watering eyes etc.
Q- 4 What are the vectors?
Ans – The animals carry the infecting agents from a sick person to another potential host. These animals are the intermediaries and are called vectors. The most common vectors are mosquitoes.
Q- 5 What is community health?
Ans – This health includes personal health with surrounding environmental health in which cleanliness of environment and social harmony also come.
Q- 6 What are the source of infection?
Ans – A source of infection can be an infected person, a mosquito, a virus and used objects of an infected person.
Q- 7 How can dehydration of the body be prevented?
Ans – If ORS (oral rehydration solution) is intake or a decent amount of water is taken then a body can be hydrated.
Q- 8 Name the vectors of the following diseases –
- Malaria – Protozoa – Female anopheles mosquito
- Dengue – Mosquito – Aedes mosquitoes
- AIDS – Virus – Human Immunodeficiency Virus (HIV)
- Amoebiasis – Protozoa
- Kala-azar – Protozoa – Leishmania
- Sleeping sickness – parasite – Trypanosoma
- Peptic ulcers – bacteria – Helicobactor pylori
- Elephantiasis – Mosquito – lymphatic filariasis
Q- 9 Name the following deficiency diseases :
- Disease caused by the deficiency of Iodine –
Ans – Goitre
- Disease caused by the biting of dog –
Ans – Rabies
- Disease caused by the deficiency of Iron –
Ans – Anemia
- Disease caused by the deficiency of Vitamin C –
Ans – Scurvy
Q- 10 Name the disease agents and the disease caused by agents?
Disease agents ——- Disease caused by them
- Bacteria – Tuberculosis, Typhoid, Cholera
- Viruses – Common cold, AIDS, Chicken pox
- Fungi – Ringworm, skin infection
- Protozoa – Malaria, Kala – azar, sleeping sickness
- Worms – Filariasis, Ascariasis
Q- 11 Define – (a) Immunization (b) Immune system (c) Immunity
Ans – (a) Immunization – Immunization is injecting vaccine for preventing from a particular diseases.
(b) Immune system – It is the system of our body which protects us from diseases.
(c) Immunity – It the ability of our body to fight with the external agent in our body for protecting from a disease.
Q- 12 What are the causes when we get disease?
Ans – Causes of disease –
- Poor immune system
- Unhygienic food and environment
- Infected by micro-organisms
- Genetic factors
Q- 13 What are the diseases caused by the spread of –
- Air borne disease – Influenza, Tuberculosis, Measles, Mumps
- Water borne disease – Typhoid, Hepatitis, Pneumonia, Cholera
- By physical contact – Polio, Covid
Q- 14 Write any two examples for these types of diseases-
- Acute Diseases – Cold, fever, Cough etc.
- Chronic Diseases – AIDS, Cancer, Diabetes etc.
- Infectious Diseases – Malaria, Typhoid, Cholera etc.
- Non-infectious Diseases – Diabetes, Heart attack, Cancer etc.
- Genetic Diseases – Haemophilia, sickle-cell anemia etc.
Q- 15 Write the target organs for the following –
- Fungal infection targets – Skin
- Fits targets – Brain
- Tuberculosis targets – Lungs
- Hepatitis targets – Liver
- Jaundice targets – Liver
- Pneumonia targets – Lungs
Q- 16 Vaccine is firstly discovered by whom? Name any two diseases prevented by using vaccines.
Ans – Vaccine is discovered by Edward Jenner. Small pox and polio can be prevented by vaccines.
Q- 17 Name any two groups of micro-organisms from which can be cured by antibiotics?
Ans – These are the groups – Bacteria, Fungi