Selina ICSE Class 9 Biology Solutions Chapter 15 Hygiene A Key To Healthy Life

Selina ICSE Solutions

Q) Multiple Choice Questions:-

1) No urination due to shortage of water in the body is a typical symptom of
a) typhoid
b) malaria
c) dysentery
d) cholera
Solution: (d) cholera

2) Which one of the following is an unhealthy habit?
a) Removing wax from inside the ears
b) Keeping the mouth closed while breathing
c) Sleeping for only 6-7 hours
d) Sharing towels with others
Solution: (d) Sharing towels with others

3) The protozoan that causes malaria is:
a) Entamoeba histolytica
b) Euglena
c) Paramecium
d) Plasmodium
Solution: (d) Plasmodium

4) The chemical substance mainly responsible for tooth disorders is
a) Calcium
b) Chloride
c) Fluorides
d) Iodides
Solution: (c) Fluorides

5) Typhoid is caused by
a) Housefly
b) Bacteria
c) Virus
d) None of the above
Solution: (b) Bacteria

6) The germ causing Hepatitis is transmitted through
a) the bite of a mosquito
b) contamination of food by a housefly
c) personal contact with a patient
d) contaminated water
Solution: (d) contaminated water

Q) Very short answer:-

1) Match the following

Selina ICSE Class 9 Biology Solutions Chapter 15 Hygiene A Key To Healthy Life


Selina ICSE Class 9 Biology Solutions Chapter 15 Hygiene A Key To Healthy Life

Q) Name The Following:-
1) Organisms that transmit microbes that causes disease.
2) Organisms that cause disease.
3) Science of maintaining good health.
(a) Organisms that transmit microbes that cause disease:- Vectors (disease carriers)
(b) Organisms that cause disease:- Pathogens
(c) Science of maintaining good health:- Hygiene

Q) Very Short Answer Type:-

Question  1) Describe the different ways by which the housefly contaminates our food.

The several ways that houseflies infect our food include:
(i) Hairy or spiny body and legs: People with hairy or spiny bodies and legs are more likely to come into contact with unsanitary conditions such rotting objects, infected wounds, or feces. These fly repeatedly rub their legs on our meal while they sit there, releasing dirt particles that contaminate it.
(ii) Spitting forth saliva: When a housefly regurgitates or discharges saliva on food, it moistens the meal and deposits germs on it. They get contaminated as a result.
(iii) Excreta: Houseflies that are feeding on food products may leave their excreta on the meal, polluting it.
(iii) Direct transfer of germs: Houseflies occasionally spread infections directly. When a fly that has been landed on an infected person’s diseased eye rests on the eyes of a healthy person, the pathogens that are present in trachoma are spread from the healthy person to the sick person.

Question 2) Suggest any two methods of controlling flies.

Two methods of controlling flies:
1. Spraying of insecticides
2. Elimination of breeding grounds

Question 3) List any three effective methods for controlling mosquitoes.

Effective methods for controlling mosquitoes:
(i) Spraying insecticides
(ii) Food should be protected by covering it
(iii) Eliminating breeding places of mosquitoes

Question 4) Name the two common kinds of mosquitoes and the diseases they transmit.

Selina ICSE Class 9 Biology Solutions Chapter 15 Hygiene A Key To Healthy Life

Question 5) Mention any three ways by which potable water can be contaminated.

Potable water contamination can be caused by:
1. Improper sewage disposal.
2. Urinating and defecating close to ponds, rivers, and lakes.
3. The discharge of animal excrement and washings from poultry and dairy operations into bodies of water


Question 1) Give suitable explanations for the following:
a) One should breathe by nose and never by mouth.
b) Hands must be washed before eating food.
c) Eating places must be kept free of flies.

(a) Because the nose has hair and mucus that trap dust and microorganisms, breathing via the mouth is never a good idea. This keeps the air you breathe clean and prevents dust and microorganisms from entering your respiratory system.
(b) In the course of our daily lives, we handle a wide range of objects, including books, coins, furniture, tools and machinery in workshops, seats and support rods in buses, and even dogs and other household animals. Many of these items are contaminated. When we contact these things, we can take up their germs, which then spread to other regions of our bodies or enter our mouths when we eat. In order to prevent the spread of illnesses brought on by these bacteria, it is imperative that we wash our hands before consuming food.
(c) A lot of bacteria and germs that cause sickness are carried by flies. In order to prevent food contamination, dining establishments must be maintained fly-free.

Question 2) How are cockroaches and rats harmful to humans?

Rats and cockroaches are frequent home pests.
(i) Food, paper, and clothing are all damaged by cockroaches. They could spread viruses, particularly cancer-causing viruses.
(ii) Rats consume grains and other meals. They serve as infection vectors as well. Rat-fleas are parasites that dwell on rats’ skin. It could be contaminated with plague spores.

Question 3) Name the two types of dysentery and their causative germs and give one main precaution against them.

Selina ICSE Class 9 Biology Solutions Chapter 15 Hygiene A Key To Healthy Life

Question 4) Mention three symptoms of the disease Hepatitis.
Below are the symptoms of hepatitis:
a) Body ache
b) Yellow eyes
c) Deep yellow urine
d) Enlarged live

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