Answer:
The process of becoming impaired
Explanation:
When you're unsure about what a word means, you can look it up in a dictionary - an alphabetically arranged listing of words that contains different information about them, such as their definitions, examples, origin, pronunciation, etc.
Another thing that can help you determine what an unfamiliar word means is context - phrases and sentences that surround it. It makes sense that cutting wheels shouldn't be stored in humid rooms or exposed to extreme temperatures. Such conditions would damage them. That means that they would become worse or, in other words, deteriorate. If we look up the word deterioration in a dictionary (e.g. Merriam-Webster dictionary), we can see that its meaning is: the action or process of becoming impaired or inferior in quality, functioning, or condition.
