NCERT Class-9 Science Solutions: Chapter 13-Why Do We Fall Ill Part 2 (For CBSE, ICSE, IAS, NET, NRA 2023)

Glide to success with Doorsteptutor material for CBSE/Class-9 : get questions, notes, tests, video lectures and more- for all subjects of CBSE/Class-9.

Question 9:

Making anti-viral drugs is more difficult than making anti-bacterial medicines because

  1. Viruses make use of host machinery
  2. Viruses are on the border line of living and non-living
  3. Viruses have very few biochemical mechanisms of their own
  4. Viruses have a protein coat

Answer: A

Image Viruses Make Use of Host Machinery

Question 10:

Which one of the following causes kala-azar?

  1. Ascaris
  2. Trypanosoma
  3. Leishmania
  4. Bacteria

Answer: C

Image the Leishmania

Question 11:

If you live in an overcrowded and poorly ventilated house, it is possible that you may suffer from which of the following diseases

  1. Cancer
  2. AIDS
  3. Air borne diseases
  4. Cholera

Answer: C

Image the Air Borne Diseases

Question 12:

Which disease is not transmitted by mosquitoes?

  1. Dengue
  2. Malaria
  3. Brain fever or encephalitis
  4. Pneumonia

Answer: D

Image Disease Transmitted Mosquitoes

Question 13:

Which one of the following is not important for individual health?

  1. Living in clean space
  2. Good economic condition
  3. Social equality and harmony
  4. Living in a large and well-furnished house

Answer: D

Question 14:

Choose the wrong statement

  1. High blood pressure is caused by excessive weight and lack of exercise.
  2. Cancers can be caused by genetic abnormalities
  3. Peptic ulcers are caused by eating acidic food
  4. Acne in not caused by staphylococci

Answer: C

Image Common Causes That Lead to Peptic Ulcers

Question 15:

We should not allow mosquitoes to breed in our surroundings because they

  1. Multiply very fast and cause pollution
  2. Are vectors for many diseases
  3. Bite and cause skin diseases
  4. Are not important insects

Answer: B

Image Diseases by Mosquitoes

Question 16:

You are aware of Polio Eradication Programmed in your city. Children are vaccinated because

  1. Vaccination kills the polio causing microorganisms
  2. Prevents the entry of polio causing organism
  3. It creates immunity in the body
  4. All the above

Answer: C

Image Polio Eradication Programme