2.1 cells

• The smallest structure that can perform life's functions is the cell
• Cells are the basic structural and functional units of all living organisms
• Cell theory states that all organisms are made of cells, which are the basic unit of life and arise from pre-existing cells
• The human body contains millions of cells
• Everything a human does results from the activities of all its cells, such as the structure and function
• Each cell is an individual unit with requirements that must be satisfied for normal function
• Cells are extremely small, requiring a microscope to see most of them
• Cells vary in size and shape, but most human cells follow a similar basic structure
• We use a microscope to view cells because they are too small to see with the naked eye
• Cells in a human body can be compared to bricks used to build a house
• Cells and bricks are both 'building blocks', with cells being the building blocks of humans and affecting the structure of a human, similar to how bricks can affect the structure of a house