* Tissues are groups of similar cells that work together to perform a specific function. For example, muscle tissue is made of muscle cells and performs movement.
* Organs are made up of different tissues that work together to perform a more complex function.
Let's look at the leaf:
* Epidermis: This outer layer of tissue provides protection and regulates gas exchange.
* Mesophyll: This layer is responsible for photosynthesis, containing chloroplasts that capture sunlight. This layer itself contains two types of tissue: palisade mesophyll and spongy mesophyll.
* Vascular tissue: This tissue, including xylem and phloem, transports water and nutrients throughout the plant.
Therefore, because a leaf contains multiple types of tissues all working together to carry out the process of photosynthesis, it is classified as an organ.
