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