1. While sneezing or coughing the little droplets are thrown out which are carried by air to persons sitting or standing nearby These infection carrying droplets are inhaled by the persons.Thus,air borne diseases such as common cold, influenza(Flu),small pox,tuberculosis,etc spread in the community.
2. All the diseases which come out of the nose or throat are being received in handkerchief which can be well washed by soap and anti-infectious substance.
(b) (1) Creating senstivity about spreading of air borne diseases .
2.Environmental protection.

(i) Sexual contact with the infected person
(ii) Transfusion of infected blood.
(iii) Use of infected syringes, or surgical equipment.
(iv) From infected mother to her unborn child.

(i) Tetanus
(ii) diptheria
(iii) Whooping cough and
(iii) measles/polio.

This is because when the immune system of our body first comes across an infectious organism like a virus causing small pox, it responds against virus and then remembers it specifically.When next time that particular microbe or its close relatives enter the body, the immune system of the body responds with the pathogen even with greater vigour.This eliminates the infection more quickly than the first time and thus we do not suffer with disease again.

(i) Viruses lack any cell well of their own.They enter our cells and use our machinery for their life processes.
(ii) They do not have cytoplasm and cell organelles.To multiply they enter the cell of living organism.They use cellular resources of the host to reproduce.
(iii) As viruses lack cells, biochemical process are missing in viruses.Since these biochemical processes are targets of antibiotics, antibiotics do not work on viruses.

(i) To reduce the effect of the disease
(ii) to kill the cause of the disease.

(i) Disease cause damage to the health and functioning of body.Sometimes, diseases may cause irrecoverable damage to some part of body as a whole.
(ii) The patient is likely to be bedridden for sometimes as treatment of the disease may take sometime.During this period his work will suffer and some person is required to look after him.
(iii) The patient of infectious disease serves as a source of spreading infection to other healthy persons.

(c) A person is more likely to fall sick when she is on a four day fast after recovering from malaria and is taking care of someone who is suffering from chicken pox. This is because she is fasting during recovery, and her immune system is so weak that it is not able to protect its own body from any foreign infection. If she is taking care of someone suffering from chicken pox, then she has more chances of getting infected from chicken pox virus and will get sick again with this disease.

The diseases which are not caused by any pathogen are called non-inectious diseases.The causes of non-infectious diseases may be
(i) Genetic abnormalities: Haemophilia, some type of cancers, etc.,
(ii) Internal causes:Such as high blood pressure can be caused by excess weight and lack of excerise.

(i) Remain away from specific and particular cause for discomfort or disease.For which personal and public cleanliness and good physical environment are necessary.
(ii) proper and sufficient food necessary for functioning of cells and tissues of the body.

'Health' is a state of being well enough to function well physically, mentally and socially.Therefore, for good health
(i) One should be disease free.
(ii) There should be social equality and harmony which are essential for individual health particularly for social and mental health.

Garbage thrown in open places, overflowing drain water or sewer, accumulation of stagnant water in ditches etc.cause spread of disease.These are the places where disease causing microbes multiply, mosquitoes and flies breed.Thus, diseases may spread in the community and hence affect individual health.

Group of diseases:
(i) Infection diseases: These diseases are caused by some parasitic organism, such as bacteria, viruses and can be transmitted to other examples of such diseases are malaria, jaundice, etc.
(ii) Non-infection diseases: They may be genetic or due to malfunctioning of internal body organ without infection.They do not spread in the community.For example, high blood pressure.