Define the terms given below:

1. Tissue
2. Organ
3. Organ system
4. Sclerenchyma
5. Cartilage

1. Tissue — A group of similar cells which are specialised to perform specific function is known as tissue. For example muscle tissue, skin tissue.

2. Organ — A differentiated structure formed by group of similar tissues, which is specialised to perform a specific function is called an organ.

3. Organ system — An organ system is a group of organs that work together to perform a specific function or set of functions in the body. For example, the digestive system.

4. Sclerenchyma — Sclerenchyma is a simple supportive permanent tissue composed of long, narrow and thick-walled dead cells. It provides strength to the plant parts.

5. Cartilage — Cartilage is a supportive connective tissue that covers the ends of bones, and gives support to certain organs like the nose, ear, and trachea. It consists of a clear ground substance (matrix), which contains a large number of spaces, each occupied by one or more cells.