Why was knowledge very restricted in the pre-paper age? (Read the text and answer the question)

Before the invention of paper there were very few books in the world because it was quite impossible to make a book with stone or heavy wood planks or metal sheets.

People looked for easy writing materials because the traditional writing materials of that age was heavy and difficult to carry and use as well.

In the pre-paper age, knowledge was very restricted because there were very few books in the world.

Paper has changed our life by making publication and the spread of knowledge and information casy.

Before the invention of writing people used to share ideas through speaking and listening.

Since writing materials were not available, it was tough to record thoughts in writing in the past.