What are the two classes of nature resources

I believe it is natural. If so. Here's your answer.

Biotic natural resources also include fossil fuels such as coal and petroleum which are formed from organic matter that has decayed. Abiotic: these resources come from non-living and non-organic material. Examples of these resources include land, fresh water, air, and heavy metals (gold, iron, copper, silver, etc.).

If not. Let me know.

The two classes of nature resources are renewable and non renewable

There are two classes of nature resources which are called renewable and non renewable. Nonrenewable energy resources, like coal, nuclear, oil, and natural gas, are available in limited supplies. Once used they cannot be recovered back. This is usually due to the long time it takes for them to be replenished. On the other hand Renewable resources are replenished naturally and over relatively short periods of time

i thinking chemical change

the tricuspid valve is present between right atrium and right ventricle