material

1. found naturally in the ground

1.1. tin

1.2. gold

1.3. granite

2. can be

2.1. man-made

2.1.1. such as

2.1.1.1. glass

2.1.1.2. nylon

2.1.1.3. plastic

2.1.1.4. styrofoam

3. can come from

3.1. plants

3.1.1. as in

3.1.1.1. wood

3.1.1.2. cotton

3.1.1.3. rubber

3.2. animals

3.2.1. as in

3.2.1.1. silk

3.2.1.2. wool

3.2.1.3. leather