Question

what does it mean by the phrase 'cycle of nature'?

here is the whole sentence:

Emily understood this cycle of nature.

Answer 1

"Definition: A natural process in which elements are continuously cycled in various forms between different compartments of the environment (e.g., air, water, soil, organisms). Examples include the carbon, nitrogen and phosphorus cycles (nutrient cycles) and the water cycle."
Glossary: Environmental cycles - GreenFacts
https://www.greenfacts.org/glossary/def/environmental-cycles.htm

Also, I would classify life and death and seasons as cycles of nature.