What is the basic difference between an unicellular organism and a multicellular organism ?

Options

A. Shape of cells
B. Size of cell
C. Functions of cells
D. Number of cells

Answer

**Step-by-Step Solution:**

1. **Definition of Unicellular Organisms:**
- Unicellular organisms are living entities that consist of a single cell. This single cell is capable of performing all the necessary functions of life, such as metabolism, reproduction, and response to the environment.

2. **Definition of Multicellular Organisms:**
- Multicellular organisms are composed of multiple cells that are specialized for different functions. These cells work together to support the life of the organism, with each type of cell performing specific roles.

3. **Basic Difference:**
- The fundamental difference between unicellular and multicellular organisms lies in the number of cells that make up the organism.
- Unicellular organisms have only **one cell**.
- Multicellular organisms have **multiple cells**.

4. **Functionality:**
- In unicellular organisms, all life processes are carried out by that single cell. In contrast, multicellular organisms have cells that are specialized for various functions, allowing for more complex life processes.

5. **Examples:**
- Examples of unicellular organisms include bacteria and amoeba. Examples of multicellular organisms include humans, trees, and animals.

**Final Answer:**
The basic difference between unicellular and multicellular organisms is the number of cells they contain. Unicellular organisms consist of a single cell, while multicellular organisms are made up of multiple cells that perform specialized functions.

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