What do you mean by hydroponics ?

Explanation

### Step-by-Step Solution:

1. **Definition of Hydroponics**: Hydroponics is a method of growing plants without soil. Instead, plants are cultivated in a nutrient-rich water solution.

2. **Nutrient Solution**: In hydroponics, the water used is not just plain water; it is enriched with mineral nutrients that are essential for plant growth. This nutrient solution provides all the necessary elements that the plants would typically extract from the soil.

3. **Support for Roots**: Since soil is not used in hydroponics, alternative substrates are employed to provide physical support to the plant roots. Common materials used for this purpose include perlite, gravel, and other inert substrates.

...