The human reproductive system helps in the production of offspring and is different in males and females.
Testes – Produce sperm and the hormone testosterone.
Scrotum – Sac that holds and protects the testes.
Produces sperm cells.
Transfers sperm to the female reproductive system.
Testes – Produce sperm and testosterone.
Scrotum – Protects the testes.
The stem is one of the main plant organs. It connects the roots to the leaves and supports the whole plant.
Holds leaves, flowers, and fruits upright.
Keeps the plant standing.
Leaves can be classified in different ways.
Have a single, undivided leaf blade.
Example: Mango, Guava.
The leaf blade is divided into smaller leaflets.
A plant cell is the basic structural and functional unit of plants.It is eukaryotic, meaning it has a true nucleus and membrane-bound organelles.Plant cells are unique because they can photosynthesize and have a rigid cell wall.
Outermost layer of the plant cell
Made mainly of cellulose
Rigid and non-living
Plants are made up of two main systems that work together to keep the plant alive.
Grows below the ground
Functions:
Absorbs water and minerals
Anchors the plant firmly in soil
Ferns are land plants with:
Well-developed roots, stems, and leaves
Structures similar to flowering plants
Birds are warm-blooded vertebrates
Body temperature remains constant
Neck vertebrae are flexible
Cold-blooded vertebrates
Four limbs
No scales; skin is moist
Name amphibian means “double life” (water + land)
Vertebrates are animals that possess a vertebral column (backbone).
Also called the spinal column or spine
Made of many cylindrical bones called vertebrae
Key Features
Wings: Usually present (one or two pairs)
Antennae: One pair
Legs: Three pairs (6 legs) attached to the thorax
Body regions: Head, thorax, abdomen
Multicellular organisms
Cells do not have cell walls or chloroplasts
Feed by ingesting solid food and digesting it internally
Animals are divided into groups called phyla
DNA is the genetic material found in almost all living organisms
It carries the instructions that tell cells how to grow, function, and reproduce
Mainly in the nucleus of a cell
A small amount is also found in mitochondria
Multicellular organisms
Cells do not have cell walls or chloroplasts
Feed by ingesting solid food and digesting it internally
Animals are divided into groups called phyla
Two important phyla discussed here:
Classification helps scientists understand how organisms are related through evolution.
Organisms that share a common ancestor are grouped together.
All vertebrates have:
A vertebral column (backbone)
Classification helps scientists understand how living things are related.
By grouping organisms with similar features, we can trace their evolutionary history.
Vertebrates are animals that have:
A vertebral column (backbone)
A dichotomous key is a tool used to identify organisms.
It works by giving two opposite choices at each step.
The word dichotomous means “two branches.”
By choosing the correct option each time, you can find the correct group or class of an organism.
A species is the smallest natural group of organisms.
Members of a species can reproduce together to produce fertile offspring.
They usually look very similar in:
Appearance
Anatomy
All living organisms—whether plants or animals, single-celled or multicellular—show seven basic characteristics. These can be remembered using the mnemonic MRS GREN.
Movement is an action by an organism or part of an organism.
It causes a change in position or place.
Example: humans walking, plants bending towards light.
MRS GREN is a memory tool used in Biology to describe the seven essential life processes that all living organisms must carry out. These processes help living things survive, grow, and reproduce.
All living organisms show movement. Animals move their whole bodies, while plants move parts like leaves, stems, or flowers. Movement helps organisms find food, escape danger, and grow towards light.
Respiration is the process of releasing energy from food. This energy is needed for every activity, including growth, repair, and movement. Plants and animals both respire.
When a very thin slice of a plant stem is looked at under a microscope, it looks like it’s made up of many small box-like parts — these are cells.
The slice in the picture is magnified 60 times. So if a cell looks 2 mm long in the image, in real life it’s only 0.03 mm long.
Such thin slices are called sections.
Longitudinal Section – Cut along the length of the stem (you see the inside part stretched out).
Viruses come in many shapes and structures.
Each virus has a core of genetic material — either RNA or DNA — surrounded by a protein coat.
They do not have:
Nucleus
Cytoplasm
Cell organelles
Includes bacteria and blue-green algae.
They are unicellular (single-celled) organisms.
No true nucleus — their DNA is not inside a nuclear membrane.
Cells are simple in structure compared to other organisms.
Some are useful (e.g. in food production), while others can cause diseases.
The epidermis is the outermost layer of cells covering the leaves, stems, and roots of a plant.
It protects the plant from water loss, injury, and infection.
Cells are closely packed and often covered with a waxy cuticle to reduce evaporation.
In leaves, it contains stomata, which control gas exchange and transpiration.
Key Points:
The Plant Kingdom (Plantae) includes all multicellular, eukaryotic, and autotrophic organisms that make their own food by photosynthesis.
They have cell walls made of cellulose.
Most plants contain chlorophyll, which gives them a green color.
They are mainly non-motile (don’t move).
Plants provide oxygen, food, and shelter for other living things.
Movement.
Respiration
Sensitivity
growth
Reproduction
Excretion
The small intestine is the main site where digested food is absorbed. Its inner wall has finger-like projections called villi, and each villus is covered with microvilli. These structures increase the surface area, making absorption faster and more efficient.
Each villus contains blood capillaries and a lymph vessel (lacteal). Different nutrients are absorbed in different ways:
Glucose and amino acids → absorbed into blood capillaries.
Fatty acids and glycerol → absorbed into lacteals.
Vitamins and minerals → absorbed depending on their solubility.
There are two main types:
Asexual Reproduction – only one parent is needed.
Offspring are identical (clones).
Examples: binary fission in bacteria, budding in yeast, vegetative propagation in plants.
Sexual Reproduction – needs two parents (male and female).
Involves gametes (sperm + egg).
Definition: The system that removes waste products from your body to keep you healthy.
Main parts & their jobs:
Kidneys – filter blood and make urine.
Lungs – remove carbon dioxide when you breathe out.
Skin – removes waste as sweat.
Liver – breaks down harmful substances (like toxins, alcohol, drugs).
The circulatory system carries blood all around the body.
The heart pumps blood.
Arteries take oxygen-rich blood from the heart to the body.
Veins bring oxygen-poor blood back to the heart.
Capillaries are tiny tubes where oxygen and nutrients go into cells, and waste like carbon dioxide comes out.
There are two pathways:
Households means the people living together in a home (like your family). In economics, we don’t just mean the building, we mean the group of people in it.
A household:
Uses goods and services (like food, clothes, electricity).
Provides resources to firms (like labour – when your parents go to work).
Earns income (wages, salary, rent, profit).
Decides how to spend money and save it.
It is so nice