Answer:It may be the only way to perpetuate particular cultivars.Or
It maintains the juvenile or adult characteristics of certain cultivars.
Explanation:
If this is not the answer you want sorry i tried my best. :)
<h2>Answer</h2>
- Wind
- Sunlight
- Plants
- Soil
- Coal
- Minerals
- Water
- Animals

In short it's natural resources.
Answer:
the answer is the white blood caells.