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Cells
All forms of life, from the biggest trees
to the microscopic organisms that swim in the smallest drop of water, are made
up of cells.
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Big or small, all living things are made of cells. |
Most organisms are made up of many types
of different cells. Some organisms, called single-celled organisms, have all
they need for life in one single cell. They can move, breathe, feed, grow,
reproduce, excrete and are sensitive even though each individual exists as a
single cell. An example of a single-celled organism is a paramecium.
Organisms which have more than one cell
are called multi-cellular organisms. Each type of cell in the organism has a
special function. In plants, for example, some cells are in charge of making
food using photosynthesis, other cells have the job of absorbing water in the
roots and still others are responsible for making the plant rigid so it will not
fall over.
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