HOTS Questions: Health: The Ultimate Treasure | Science Curiosity Class 8 - New NCERT PDF Download

1. The most common carrier of communicable diseases is

(a) Ant
(b) Housefly
(c) Dragonfly
(d) Spider

Ans: b
The housefly is the most common carrier of communicable diseases. Here are some key points:

• Houseflies can carry harmful pathogens from waste to food.
• They often land on contaminated surfaces, picking up germs.
• When they touch uncovered food, they can transfer these germs, leading to illness.
• To prevent disease, always cover food and maintain good hygiene.

Housefly

2. The following is an antibiotics

(a)    Alcohol

(b)   Yeast

(c)    Sodium bicarbonate

(d)   Streptomycin

Ans: d

3. Cholera is caused by

(a)   Bacteria

(b)   Virus

(c)   Protozoa

(d)   Fungi

Ans: a

• Cholera is caused by bacteria.
• These bacteria are known as Vibrio cholerae.
• Cholera is primarily transmitted through contaminated water or food.

4.  Carrier of dengue virus is

(a)   House fly

(b)   Dragon fly

(c)   Female Aedes Mosquito

(d)   Butterfly

Ans: c
The carrier of the dengue virus is the female Aedes mosquito. This mosquito is responsible for transmitting the virus to humans through its bites.

• The dengue virus is not spread by common insects like houseflies or butterflies.
• It is crucial to control the population of Aedes mosquitoes to prevent dengue outbreaks.

5.  The vaccine for smallpox was discovered by

(a)    Robert Koch

(b)   Alexander Fleming

(c)    Sir Ronald Ross

(d)   Edward Jenner

Ans: d
Edward Jenner is credited with the discovery of the smallpox vaccine in 1798. His work laid the foundation for modern vaccination practices. Here are some key points about his contribution:

• Jenner used material from cowpox lesions to create immunity against smallpox.
• This method demonstrated that exposure to a related, less harmful virus could protect against a more dangerous one.
• His discovery significantly reduced the incidence of smallpox, leading to its eventual eradication.

6. Chickenpox is caused by

(a)    Virus

(b)   Fungi

(c)   Protozoa

(d)   Bacteria

Ans: a

• Chickenpox is caused by a virus.
• It spreads through air or direct contact with an infected person.
• Common symptoms include itchy rashes and fever.

7. Plasmodium is a human parasite which causes

(a)   dysentery

(b)  Sleeping sickness

(c)   Malaria

(d)   All of the above

Ans: c

• Plasmodium is a type of protozoan parasite.
• It is responsible for causing malaria in humans.
• Malaria is transmitted through the bite of infected female Anopheles mosquitoes.
• Symptoms of malaria include fever, chills, and flu-like illness.

Thus, the correct answer is C) Malaria.

8. Carrier of malaria causing protozoan is

(a)   Butterfly

(b)   Housefly

(c)   Female Anopheles Mosquito

(d)   Cockroach

Ans: c
The carrier of the malaria-causing protozoan is the female Anopheles mosquito. Here are some key points:

• Malaria is caused by a parasite called Plasmodium.
• The female Anopheles mosquito is essential for transmitting this parasite.
• Other insects, like houseflies and cockroaches, do not transmit malaria.

9. Foot and mouth disease of cattle is caused by

(a)   Fungi

(b)   Virus

(c)    Algae

(d)   None of these

Ans: b
Virus Foot and mouth disease in cattle is caused by a virus. This highly contagious viral infection affects cloven-hoofed animals, leading to:

• Blisters in the mouth and on the feet
• Fever and drooling
• Loss of appetite and weight

Effective control measures include:

• Vaccination of livestock
• Quarantine of infected animals
• Strict hygiene practices on farms

Q10: How do antibiotics work, and why is it important to complete the prescribed course of antibiotics?
Ans: Antibiotics are medicines that kill or inhibit the growth of disease-causing microorganisms. It's essential to complete the prescribed course to ensure all the pathogens are eliminated. Incomplete courses may lead to the development of antibiotic-resistant strains and make future infections more challenging to treat.

Q11: Describe the role of antibiotics in controlling microbial infections. Why is it crucial to use antibiotics responsibly?
Ans: Antibiotics control microbial infections by killing or inhibiting the growth of bacteria. Using antibiotics responsibly is crucial to prevent the development of antibiotic-resistant strains and to avoid harming beneficial bacteria in the body.

Q12: Microorganisms that causes disease are also known as:
(a) pathogens
(b) fungi
(c) antigen
(d) microbes
Ans: (a)
Explanation: Pathogens are microorganisms, such as bacteria, viruses, and fungi, that can cause diseases in their hosts. They are responsible for various infectious diseases.

Q13: Pathogens are also called
(a) germs
(b) antigen
(c) antibody
(d) carrier
Ans: (a)
Explanation: "Germs" is a colloquial term often used to refer to disease-causing microorganisms or pathogens. It's a simple way to describe the microorganisms that can make people sick.

Q14: Seema got cough and cold badly. Her teacher asked her to take rest at home and use handkerchief while sneezing and coughing. She obeyed her teacher.

1. Why should we keep a handkerchief on nose and mouth while sneezing or coughing?
2. What are the modes of transfer of diseases from infected to healthy person?
3. Do you think Seema’s teacher decision was right? Why?
4. What value of Seema is shown here?

Ans:

1. We should keep a handkerchief on nose and mouth while sneezing or coughing because fine drop-lets carrying thousands of viruses or bacteria spread in the air.
2. Air, water, food, carriers and physical contact.
3. Yes, because cough and cold spreads through air and there are chances that other students may also get infected.
4. Seema is an obedient girl.