Cells are structural and functional unit of living organisms.

Explanation

### Step-by-Step Text Solution:

1. **Understanding the Definition of Cells**:
- Cells are defined as the basic structural and functional units of all living organisms. This means that every living organism is composed of cells, which carry out the necessary functions for life.

2. **Types of Organisms**:
- Living organisms can be classified into two main categories: multicellular organisms and unicellular organisms.
- **Multicellular organisms** (like humans, scientifically known as Homo sapiens) consist of many cells that work together to perform various functions.
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