For Class 8, 9 & 10
Foundation - a strong base in Physics, Chemistry, Maths & Biology
Concept-first questions with clear model answers across all four subjects, aligned to NCERT. Start early, build the habit, and walk into your board exams, NEET and JEE already ahead.
Showing 1 question in Biology for Class 8. Tap a card to reveal the answer.
BiologyMicroorganisms: Friend and FoeeasyName two useful and two harmful micro-organisms and state what they do.
Reveal answer ↓
What it is
Microbes are tiny living things that can help us (curd, bread, medicine) or harm us (disease).
Answer
Useful: yeast is used to make bread and in brewing (fermentation), and Lactobacillus bacteria turn milk into curd. Harmful: the bacterium that causes tuberculosis, and the Plasmodium protozoan that causes malaria. So micro-organisms can help or harm us depending on the type.
- •Useful: yeast (bread, fermentation), Lactobacillus (curd)
- •Harmful: TB bacteria, malaria (Plasmodium)
- •Microbes can be helpful or disease-causing
Why learn this
They set your curd, raise your bread and cause colds - biology you meet every day.
💡 Memory trick
Friends Ferment (curd and bread); Foes cause Fever.