Our bodies contain over 30 trillion specialized cells that are organized into tissues. A tissue is a group of similar cells that work together to perform a specific function. There are two main types of tissues - plant tissues which are made of thick-walled, often dead cells that allow plants to grow throughout their lives, and animal tissues containing mostly living cells that enable animal mobility and heterotrophic nutrition but limit further growth after maturity.

2. Let Us Recap:
• Cells are the basic structural and functional unit of life.
• Organisms can be classified into two types: unicellular (having
only one cell) and multicellular (having multiple cells).
• Our body has over 30 trillion cells.
• All our cells do not perform the same function.
• They are specialized to increase efficiency of the organism.

3. What are Tissues?
A group of cells similar in structure and function, and
having a common origin is called a tissue.
Example of a Tissue

4. Types of Tissues
Tissues are of two types – plant tissues and animal tissues.
Both plants and animals are living organisms. However, there are various
differences in their structure, function, nutrition and growth.
• Most plant cells are dead and thick-walled while most animal cells are living.
• Plants are autotrophic and stationary, while animals are heterotrophic and mobile.
• Plants grow throughout their life, while animals stop growing after a point.