NCERT Solutions – Class 9 Science Questions Answers Q1. How many of these ways we can think of are events that would occur when the disaster is actually happening? Ans. (i) Disease caused due to shortage of drinking water. (ii) Health affected by the shortage of food. (iii) Diseases caused to due sanitary problems. (iv) Health affected due to unavailabilities of shelter. Q2. How many of these health-related events would happen long after the actual disaster, but would still be because of the disaster? Ans. (i) Diseases caused due to accumulation of dirty water e. g. , malaria. (ii) Spread of water borne diseases like cholera, dysentry etc. (iii) Diseases caused due to rotting things in the debris. Q3. Why would one effect on health fall into the first group, and why would another fall into the second group? Ans. This is because the disease or the effect on health which are placed in the first group are caused immediately after the disaster takes place. But, the effect or diseases in the second group, however are ultimately due to disaster, but takes time to take place. Q4. List any three reasons why you would think that you are sick and ought to seek a doctor. If only one of these symptoms were present, would you still go to the doctor? Why or why not? Ans. If any of the above symptoms is observed, the person should immediately contact the doctor.
Cause : Any of the symptoms can be the cause of disease. If these are ignored, the person may have to face a dangerous situation. Q5. In which of the following case do you time the long-term effects on your health are likely to be most unpleasant? (i) If you get jaundice (ii) If you get lice. (iii) If you get a acne. Ans. In Jaundice because, it is a chronic disease which may stay for a long-time. Q6. Why are we normally advised to take bland and nourishing food when we are sick? Ans. During infection, the immune power of the body decreases. So, to maintain the immune power we are suggested to take sufficient and easily digestible food. Q7. What are the different means by which infectious diseases are spread? Ans. (i) By air : By sneezing and coughing, the microbes spread into the air and enter the body of healthy man. (ii) By water : The microbes enter our body by drinking polluted and contaminated water. (iii) By sexual contact : some disease like AIDS, spread by sexual contact with infected person. (iv) By vectors : Some organisms like female anopheles mosquito also work as the vector of disease causing agent and hence spread diseases. Q8. What precautions can you take in your school to reduce the incidence of infectious diseases? Ans. (i) By preventing gathering of people. (ii) By making available clean and fresh drinking water. (iii) By keeping ground and class rooms clean. (iv) By using handkerchief to cover mouth while sneezing or coughing. (v) By preventing accumulation of water in and around the school. (vii) By keeping the toilet clean. (viii) By avoiding the use of uncovered food and fruits.
Q9. What is immunisation? Ans. The process of developing immune power in the body to fight against the diseases is called immunisation. Q10. 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? Ans. (a) Some particular symptoms e. g. , cough, cold, dysentery, etc. Indicate that child is sick. (b) (i) Every disease has its own particular symptoms which tell us about the disease. (ii) By carrying tests in the laboratory, the disease can be diagnosed. Q11. 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. Why? Ans. (c) When she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox.
Reason : (a) due to unavailability of sufficient and balanced diet and weakened immune system. (Page No. 178) 1. State any two conditions essential for good health. Ans. (i) (ii) 2. State any two conditions essential for being free of disease. Ans. (i) (ii) 3. Are the answers to the above questions necessarily the same or different? Why? Ans. Answers though not identical are similar because for being disease free one needs to be physically and mentally healthy. (Page No. 180) 1. List any three reasons why you would think that you are sick and ought to see a doctor. If only one of these symptoms were present, would you still go to the doctor? Why or why not? Ans. If we have fever, headache, stomachache, loose motions, cough and sneeze etc we feel weak. Then we would that we are sick and ought to see a doctor. If only one of these symptoms were present we should still go to see the doctor. Any of these symptoms may be initial signs of a severe disease. 2. In which of the following case do you think the long-term effects on your health are likely to be most unpleasant? в if you get jaundice, в if you get lice, в if you get acne. Why? Ans. The long-term effects on our health are likely to be most unpleasant if we get jaundice because the symptoms severely affect our internal organs and persist for long time. (Page No. 187) 1.
Why are we normally advised to take bland and nourishing food when we are sick? Ans. 1. We are normally advised to take bland and nourishing food when we are sick because we are weak during illness and need complete nourishment for faster recovery. 2. What are the different means by which infectious diseases are spread? Ans. a) b) c) through vectors or carriers (housefly, mosquito etc) d) e) 3. What precautions can you take in your school to reduce the incidence of infectious diseases? Ans. (i) (ii) (iii) 4. What is immunisation? Ans. Immunisation is a method of preparing memory cells in immune system. In this method weak or dead microbes of disease are injected in the body such that develop memory lymphocytes(WBCs) but do not cause disease. eg vaccination against polio, tetanus etc. 5. What are the immunisation programmes available at the nearest health centre in your locality? Which of these diseases are the major health problems in your area? Ans. DPT vaccine: it is for diphtheria, pertussis and tetanus in infants. Pulse polio vaccine: it is to prevent polio. BCG vaccine: bacillus calmette Guerin vaccine for tuberculosis. TAB vaccine for typhoid. tuberculosis and diarrhea are the major health problems in our area.