materials

1. can be

1.1. found naturally in groud

1.1.1. such as

1.2. tin

1.3. gold

1.4. granite

2. man-made

2.1. such as

2.1.1. nylon

2.1.2. glass

2.1.3. plastic

2.1.4. styrofoam

3. plants

3.1. as in

3.2. wood

3.3. cotton

3.4. rubber

4. amimal

4.1. as in

4.2. wood

4.3. slik

4.4. leather