Teacher: Given a scientific passage and an answer, generate a question for the given answer.
Teacher: Now, understand the problem? If you are still confused, see the following example:
Passage: A frameshift mutation is a deletion or insertion of one or more nucleotides that changes the reading frame of the base sequence. Deletions remove nucleotides, and insertions add nucleotides. Consider the following sequence of bases in RNA:. Answer: nucleotides.
Solution: A frameshift mutation is a deletion or insertion of one or more of what that changes the reading frame of the base sequence?
Reason: The science passage defines frame mutation and the main compoment here is nucleotides. Hence the generated question is apt.

Now, solve this instance: Passage: When a solid substance is involved in a chemical reaction, only the matter at the surface of the solid is exposed to other reactants. If a solid has more surface area, more of it is exposed and able to react. Therefore, increasing the surface area of solid reactants increases the reaction rate. For example, crushing a solid into a powder exposes more of the substance to other reactants. This may greatly speed up the reaction. You can see another example in Figure below . Iron rusts when it combines with oxygen in the air. The iron hammer head and iron nails will both rust eventually. Which will rust faster?. Answer: the surface
Student:
When a solid substance is involved in a chemical reaction, only the matter from which part of the solid is exposed to other reactants?