The total number of biodegradable materials among the following is ________ .
metallic can, peels of orange, aluminium wire, newspaper cuttings, tyre, plastic ball

Explanation

To determine the total number of biodegradable materials from the list provided, we need to analyze each item based on whether it can be broken down by natural processes, particularly by bacteria.

### Step-by-Step Solution:

1. **Identify the materials**: The items given in the question are:
- Metallic can
- Peels of orange
- Aluminium wire
- Newspaper cuttings
- Tyre
- Plastic ball

2. **Evaluate each material**:
- **Metallic can**: This is made of metal and does not biodegrade. **(Not biodegradable)**
- **Peels of orange**: This is organic waste and can be broken down by bacteria. **(Biodegradable)**
- **Aluminium wire**: Like the metallic can, aluminium does not biodegrade. **(Not biodegradable)**
- **Newspaper cuttings**: Made from paper, which is organic, and can be decomposed by bacteria. **(Biodegradable)**
- **Tyre**: Made from rubber, tyres are not biodegradable and can take a long time to decompose. **(Not biodegradable)**
- **Plastic ball**: Plastic is synthetic and does not decompose easily. **(Not biodegradable)**

3. **Count the biodegradable materials**:
- From the evaluation, the biodegradable materials identified are:
- Peels of orange
- Newspaper cuttings
- Therefore, there are a total of **2 biodegradable materials**.

### Final Answer:
The total number of biodegradable materials among the following is **2**.

---