organs, cells, tissues

• organelle

  a component inside a cell that carries out a particular task
• examples of organelles

  chloroplast, cilia
• cell

  the basic functional unit of living organisms
• examples of cells

  neurone, guard cell, white blood cells, etc
• tissue

  a collection of similar cells carrying out a particular function
• examples of tissues

  retina, palisade mesophyll
• organ

  a collection of different tissues which work together to perform a common function
• examples of organs

  eye, flower, leaf
• system


  a group of organs working together to perform an overall function for the organism
• examples of systems


  transport system, reproductive system