Class 8 Science


Extra Questions

Multiple Choice Questions

Question 1: Which microbe is used for production of alcohol?

  1. Yeast
  2. Plasmodium
  3. Lactobacillus
  4. Rhizobium

    Answer: (a) Yeast

Question 2: How much nitrogen is present in the atmosphere?

  1. 78%
  2. 88%
  3. 68%
  4. 58%

    Answer: (a) 78%

Question 3: Malaria is caused by which type of microbe?

  1. Bacteria
  2. Fungi
  3. Algae
  4. Protozoa

    Answer: (d) Protozoa

Question 4: Common cold is caused by which type of microbe?

  1. Bacteria
  2. Virus
  3. Algae
  4. Fungi

    Answer: (b) Virus

Question 5: Which of the following diseases is caused by a fungus?

  1. Cholera
  2. Common cold
  3. Ringworm
  4. Dengue

    Answer: (c) Ringworm

Question 6: Which of the following helps in making curd from milk?

  1. Lactobacillus
  2. Plasmodium
  3. Yeast
  4. Salmonella

    Answer: (a) Lactobacillus

Question 7: Antibiotics are effective against which of the following?

  1. Bacteria
  2. Fungi
  3. Virus
  4. All of the above

    Answer: (a) Bacteria

Question 8: Penicillin was discovered by which scientist?

  1. Edward Jenner
  2. Louis Pasteur
  3. Alexander Fleming
  4. Robert Koch

    Answer: (c) Alexander Fleming

Very Short Answer Type Questions

Question 1: What are microorganisms?

Answer: Organisms which cannot be seen by naked eyes are called microorganisms or microbes.

Question 2: What is an antibiotic?

Answer: A substance which kills or stops the growth of bacteria is called antibiotic.

Question 3: What is fermentation?

Answer: The process of conversion of sugar into alcohol by yeast through anaerobic respiration is called fermentation.

Question 4: What is Polio?

Answer: Polio is a disease which affects nerves and results in paralysis; especially of legs.

Question 5: What is communicable disease?

Answer: A disease which can spread from one person to another is called communicable disease.

Question 6: What is a pathogen?

Answer: A microorganism which causes disease is called a pathogen.

Question 7: What is food preservation?

Answer: Use of some techniques to prolong the shelf life of a food is called food preservation.

Question 8: What is nitrogen fixation?

Answer: The process of changing atmospheric nitrogen into compounds of nitrogen so that plants can take up nitrogen is is called nitrogen fixation.

Question 9: What is nitrogen cycle?

Answer: The sequence of events by which nitrogen is channelized to the living world and back to atmosphere is called nitrogen cycle.