Final answer:
The subject of this question is materials engineering. The material being described is cheap, relatively soft, breaks easily, and absorbs moisture. It is commonly used for folding rules, and based on the given information, it is likely referring to paper.
Step-by-step explanation:
The subject of this question is materials engineering. The material being described is a cheap and relatively soft substance that breaks easily, absorbs moisture, and is used for folding rules. Based on the provided information, this material exhibits properties such as being weak, lightweight, and absorbent, which are commonly associated with paper.