it is a phrase becuase a phrase is a group of words that may contain either a subject or a verb but not both and the sentence "swimming laps at the pool" only contians a subject becuase, who is swimming laps at the pool?
no, this is because it can cause a lot of effects later on in their lives.
To take a stand can mean a lot of things, like supporting your ideas and beliefs. At times, people support and idea or belief to such an extent that they would die just to defend it.