Unicellular Organisms: living things that are made of 1 cell

• Bacteria
• Algae
• Most are primitive with no nucleus

Multicellular Organisms: living things that are made of 2 or more cells working together

• Humans
• Trees
• Snails

Multicellular Organisms have groups of cells that work together to carry out the life processes

• Groups of the same kind of cells that work together to carry out a specific job: TISSUE

• Groups of similar tissues that work together to carry out a specific job: ORGAN

• Group of organs that work together to carry out a life process: ORGAN SYSTEM

• Group of organ systems working together to allow the organism to survive