Life begins from a single cell. This single cell divides repeatedly and forms many cells. In multicellular organisms, these cells do not work randomly. Cells become specialised and form tissues, tissues form organs, organs form organ systems, and organ systems together form the complete organism.
A tissue is a group of similar cells that work together to perform a particular function.
For example:
| Organism | Tissue | Function |
|---|---|---|
| Animals | Muscle tissue | Helps in movement |
| Animals | Nervous tissue | Carries messages and coordinates body activities |
| Plants | Xylem | Transports water and minerals |
| Plants | Phloem | Transports food |
The formation of tissues leads to division of labour, which means different groups of cells perform different functions. This makes the body more efficient.
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