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 6 questions in Biology for Class 8. Tap a card to reveal the answer.
BiologyCell Structure and FunctionseasyGive two differences between a plant cell and an animal cell.
Reveal answer ↓
What it is
Plant cells have a cell wall, a big vacuole and chloroplasts; animal cells have none of these.
Answer
A plant cell has a rigid cell wall outside its cell membrane and usually contains a large central vacuole and green chloroplasts for photosynthesis. An animal cell has no cell wall (only a cell membrane), has small or no vacuoles and lacks chloroplasts. This is why plants can make their own food while animals cannot.
- •Plant cell: cell wall, large vacuole, chloroplasts
- •Animal cell: no cell wall, small/no vacuole, no chloroplasts
- •Chloroplasts let plants photosynthesise
Why learn this
It's why plants stand upright and make their own food, while animals must eat.
💡 Memory trick
Plants carry a 'WCV' kit: Wall, Chloroplast, big Vacuole.
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.
BiologyCrop Production and ManagementmediumWhat is the difference between manure and fertiliser?
Reveal answer ↓
What it is
Manure is natural and releases nutrients slowly; fertiliser is a chemical that acts fast.
Answer
Manure is a natural substance made by decomposing animal dung and plant waste; it adds humus, improves soil texture and releases nutrients slowly. A fertiliser is a chemical made in factories that is rich in a specific nutrient (like nitrogen, phosphorus or potassium) and acts fast, but its overuse can harm the soil and water. Manure is eco-friendly; fertilisers give a quick nutrient boost.
- •Manure: natural, from decomposed waste, adds humus, slow
- •Fertiliser: chemical, nutrient-specific, fast-acting
- •Overuse of fertiliser harms soil and water
Why learn this
It's the core of the organic-farming versus chemical-farming debate and of soil health.
💡 Memory trick
Manure = Made by Nature; Fertiliser = Factory-made and Fast.
BiologyReaching the Age of AdolescencemediumWhat are secondary sexual characters, and which glands control them?
Reveal answer ↓
What it is
At puberty, hormones bring body changes that mark a child becoming an adult.
Answer
Secondary sexual characters are the physical features that appear at puberty and distinguish males from females - such as growth of facial hair and deepening of the voice in boys, and development of breasts in girls. They are controlled by hormones released by the endocrine glands: testosterone from the testes in boys and oestrogen from the ovaries in girls.
- •Features appearing at puberty that distinguish the sexes
- •Boys: facial hair, deep voice (testosterone)
- •Girls: breast development (oestrogen)
- •Controlled by endocrine hormones
Why learn this
It helps you understand your own body's changes calmly and scientifically.
💡 Memory trick
Testes make Testosterone (boys); Ovaries make Oestrogen (girls).
BiologyReproduction in AnimalseasyWhat is the difference between oviparous and viviparous animals? Give one example of each.
Reveal answer ↓
What it is
Animals either lay eggs (oviparous) or give birth to live young (viviparous).
Answer
Oviparous animals lay eggs that develop and hatch outside the mother's body, for example a hen or a frog. Viviparous animals give birth to live young that develop inside the mother's body, for example a human or a cow.
- •Oviparous: lay eggs, develop outside (hen, frog)
- •Viviparous: give birth to live young, develop inside (human, cow)
Why learn this
It helps you understand how different animals - and humans - are born and develop.
💡 Memory trick
Oviparous = Ova (eggs) outside; Viviparous = Vivid live babies inside.
BiologyConservation of Plants and AnimalseasyWhat is biodiversity, and why should it be conserved?
Reveal answer ↓
What it is
Biodiversity is the variety of all living things - plants, animals and microbes - in an area.
Answer
Biodiversity is the variety of living organisms - plants, animals and micro-organisms - found in a particular area. It should be conserved because every species has a role in keeping the ecosystem balanced, and the loss of one can affect many others. Biodiversity gives us food, medicines, and clean air and water, and losing it through deforestation and pollution can push species to extinction.
- •Variety of living things in an area
- •Each species helps keep the ecosystem balanced
- •Gives food, medicine, clean air and water
- •Threats: deforestation and pollution -> extinction
Why learn this
Protecting it keeps ecosystems, food and medicines healthy for the future.
💡 Memory trick
Bio-diversity = the 'variety of life'. More variety = a stronger, healthier ecosystem.