1. They were quickly responding to <b>customer needs</b>.<br/><br/>2. They were quickly responding to <b>customers' needs</b>. <br/><br/>I wonder which one is correct (or more natural)?<br/><br/>When making another noun with two nouns (customer + needs), do i need to use singular or plural (customer or customers)?<br/><br/>It's so confusing. (I wonder whether my question makes sense)<br/><br/>Thanks in advance.