Here we provide NCERT Solutions for Class 9 Science Chapter 13 – Why do We Fall ill? for English medium students, Which will very helpful for every student in their exams. Students can download the latest NCERT Solutions for Class 9 Science Chapter 13 pdf. Now you will get step by step solution to each question. 2. What are the different means by which infectious diseases are spread?
The different modes of transmission of infectious diseases are:
→ Through Air: Certain disease-causing micro-organisms are expelled in air by coughing, sneezing, talking, etc. These micro-organisms can travel through dust particles or water droplets in air to reach other people. For example, tuberculosis, pneumonia, etc. spread through air.
→ Through Water: Sometimes causal micro-organisms get mixed with drinking water and spread water borne diseases. Cholera for example is water borne disease.
→ Through Sexual Contact: Sexual act between two people can lead to the transfer of diseases such as syphilis, gonorrhoea, AIDS, etc.
→ Through Vectors: Certain diseases spread by animals called vectors. For example mosquitoes spread malaria.
3. What precautions can you take in your school to reduce the incidence of infectious diseases?
Precautions to reduce incidence of infectious diseases are:
→ Staying away from the infected person.
→ Covering mouth or nose while coughing or sneezing to prevent the spread of disease.
→ Drinking safe water.
→ Keeping the school environment clean to prevent multiplication vectors.
4. What is immunization?
Immunizationis defined as protection of the body from communicable diseases by administration of some agent that mimics the microbe.
5. What are the immunization programmes available at the nearest health centre in your locality? Which of these diseases are the major health problems in your area?
The immunization programmes available at the nearest health centre are DPT (Diphtheria, Pertusis, and Tetanus), polio vaccine, hepatitis B, MMR (Measles, Mumps, and Rubella), jaundice, typhoid, etc.
Of all these diseases, jaundice and typhoid are major health problems.
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2. A doctor/nurse/health-worker is exposed to more sick people than others in the community. Find out how she/he avoids getting sick herself/himself.
The following precautions must be taken by a doctor/ nurse/ health-worker:
→ Wearing a mask when in contact with a diseased person.
→ Keeping yourself covered while moving around an infected place.
→ Drinking safe water.
→ Eating healthy and nutritious food.
→ Ensuring proper cleanliness and personal hygiene.
4. A baby is not able to tell her/his caretakers that she/he is sick. What would help us to find out
(a) that the baby is sick?
(b) what is the sickness?
(a) The baby is sick can be determined by his/her behavioural changes such as constant crying of baby, improper intake of food, frequent mood changes, etc.
(b) The sickness is determined by symptoms or indications that can be seen in the baby. The symptoms include vomiting, fever, loose motion, paleness in the body, etc.
5. Under which of the following conditions is a person most likely to fall sick?
(a) when she is recovering from malaria.
(b) when she has recovered from malaria and is taking care of someone suffering from chicken-pox.
(c) when she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox.
(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.
6. Under which of the following conditions are you most likely to fall sick?
(a) when you are taking examinations.
(b) when you have travelled by bus and train for two days.
(c) when your friend is suffering from measles.
(c)You are more likely to fall sick when your friend is suffering from measles. This is because measles is highly contagious and can easily spread through respiration i.e., through air. Thus, if your friend is suffering from measles, stay away from him otherwise you might easily get infected with the disease.
All Subject NCERT Solutions For Class 9
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