What is a reduction reaction?
Identify the substances that are oxidised and the substances that are reduced in the following reaction.
`Fe_2O_3+2Al toAl_2O_3+2Fe`

Explanation

### Step-by-Step Solution:

1. **Definition of Reduction Reaction**:
A reduction reaction is a chemical process where a substance gains electrons, which can occur through the removal of oxygen or the addition of hydrogen. In simpler terms, it is characterized by the decrease in oxidation state of a substance.

**Hint**: Remember that reduction involves gaining electrons or losing oxygen.

2. **Understanding the Given Reaction**:
...