Class 8 Science
Multiple Choice Questions
Question 1: Which microbe is used for production of alcohol?
Answer: (a) Yeast
Question 2: How much nitrogen is present in the atmosphere?
Answer: (a) 78%
Question 3: Malaria is caused by which type of microbe?
Answer: (d) Protozoa
Question 4: Common cold is caused by which type of microbe?
Answer: (b) Virus
Question 5: Which of the following diseases is caused by a fungus?
- Common cold
Answer: (c) Ringworm
Question 6: Which of the following helps in making curd from milk?
Answer: (a) Lactobacillus
Question 7: Antibiotics are effective against which of the following?
- All of the above
Answer: (a) Bacteria
Question 8: Penicillin was discovered by which scientist?
- Edward Jenner
- Louis Pasteur
- Alexander Fleming
- Robert Koch
Answer: (c) Alexander Fleming
Very Short Answer Type Questions
- What are microorganisms?
Answer: Organisms which cannot be seen by naked eyes are called microorganisms or microbes.
- What is an antibiotic?
Answer: A substance which kills or stops the growth of bacteria is called antibiotic.
- What is fermentation?
Answer: The process of conversion of sugar into alcohol by yeast through anaerobic respiration is called fermentation.
- What is Polio?
Answer: Polio is a disease which affects nerves and results in paralysis; especially of legs.
- What is communicable disease?
Answer: A disease which can spread from one person to another is called communicable disease.
- What is a pathogen?
Answer: A microorganism which causes disease is called a pathogen.
- What is food preservation?
Answer: Use of some techniques to prolong the shelf life of a food is called food preservation.
- 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.
- 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.