Answer:
The chair is made of wood.
Explanation:
Made of is used when the material the subject consists of doesn't change during the process of making the subject.
e.g. Chairs are made of wood.
Here, wood is still wood. It doesn't transform into something else.
On the other hand, made from is used when the material changed its nature.
e.g. Paper is made from wood.
Now, wood disappeared — it was transformed into paper.
