NCERT In Text

State any two conditions essential for good health.

The two conditions essential for good health are:

(i) An individual must have better health facilities and more professionals to deal with health problems.

(ii) All basic necessary conditions to prevent diseases must be present. For example, proper garbage collection and disposal, clearing of drains, supply of healthy drinking water, etc

Related Questions Why Do We Fall ill

Because of strong immune system our body is normally fighting off microbes. We have cells which are specialised to kill the pathogenic microbes. These cells are active when infecting microbes enter the body and if they are successful in removing the pathogen, we remain disease– free. So even if we are exposed to infectious microbes, it is not necessary that we suffer from diseases.

11. If you live in an overcrowded and poorly ventilated house, it is possible that you may suffer from which of the following diseases
(a) Cancer
(b) AIDS
(c) Air borne diseases
(d) Cholera
Ans. (c) Air borne diseases
Explanation: Living in enclosed spaces increases the risk of air-borne diseases.

12. Which disease is not transmitted by mosquitoes?
(a) Dengue
(b) Malaria
(c) Brain fever or encephalitis
(d) Pneumonia
Ans. (d) Pneumonia
Explanation: Pneumonia is transmitted through air.

13. Which one of the following is not important for individual health?
(a) Living in clean space
(b) Good economic condition
(c) Social equality and harmony
(d) Living in a large and well-furnished house
Ans. (d) Living in a large and well-furnished house
Explanation: If a large and well-furnished house is not clean; then it is not enough to ensure health. Conditions shown in other options are more important for being healthy.

14. Choose the wrong statement
(a) High blood pressure is caused by excessive weight and lack of exercise.
(b) Cancers can be caused by genetic abnormalities
(c) Peptic ulcers are caused by eating acidic food
(d) Acne in not caused by staphylococci
Ans. (c) Peptic ulcers are caused by eating acidic food
Explanation: Peptic ulcers are caused by a bacterium known as Helicobacter pylori.

15. We should not allow mosquitoes to breed in our surroundings because they
(a) multiply very fast and cause pollution
(b) are vectors for many diseases
(c) bite and cause skin diseases 
(d) are not important insects
Ans. (b) are vectors for many diseases
Explanation: Diseases spread by mosquitoes are very dangerous; like malaria and dengue. Hence, it is important to prevent the breeding of mosquitoes.

16. You are aware of Polio Eradication Programme in your city. Children are vaccinated because
(a) vaccination kills the polio causing microorganisms
(b) prevents the entry of polio causing organism
(c) it creates immunity in the body
(d) all the above
Ans. (c) it creates immunity in the body
Explanation: Any vaccine helps in creating immunity in the body against a particular disease for which the vaccine is being made.

17. Viruses, which cause hepatitis, are transmitted through
(a) air
(b) water
(c) food
(d) personal contact
Ans. (b) water
Explanation: Hepatitis is a viral disease and spreads through contaminated water. But hepatitis B is spread through exchange of body fluids.

18. Vectors can be defined as
(a) animals carry the infecting agents from sick person to another healthy person
(b) microorganisms which cause many diseases
(c) infected person
(d) diseased plants
Ans. (a) animals carry the infecting agents from sick person to another healthy person Explanation: Vectors are in fact live carries of germs of diseases.

(i) Sleeping sickness caused by Trypanosoma/ Malaria by plasmodium
(ii) Kala-azar caused by Leishmania

When the functioning or the appearance of one or more systems of the body will change for the worse, it gives certain abnormal signs of the disease. These visual changes in human beings are called symptoms. Symptoms give indication of the presence of a particular disease.
Example (i) Lesions on the skin are the symptoms of chickenpox.
Example (ii) Cough is the symptom of lung infection.

Antibiotics generally block the biosynthetic pathways and they block these pathways of the microbes/bacteria. However, viruses have very few biochemical mechanisms of their own and hence are unaffected by antibiotics.