"Will a doctor take a biopsy during a colonoscopy no matter what?"
I'm not sure. I know they take a biopsy if they find a polyp
"According to my mom, the doctor said he didn't see anything too abnormal, but he took 3+ biopsies."
Who had the colonoscopy? Did your doc tell your mom because you were sedated? He probably found 3 polyps....
"My primary care doctor said they wouldn't take biopsies unless there was something clearly wrong, which obviously makes me nervous."
A polyp does not mean something is wrong. They just remove them in case there is a problem.
"What are the biopsies for?"
I had one done because my gastro found a polyp during my endoscopy.
Before you get discharged, the gastro will give you a picture of where she made the incision! And he/she will explain what the biopsy is for etc.. I was half-awake so take someone that can accurately tell you the right info. They will usually tell you not to worry and tell you it's not cancer etc..
"What can they indicate, like, what can the results diagnose?"
They told me to wait two weeks to get my results! I drove myself crazy
thinking of the worst (cancer etc..) I looked up lot's of things online and just made everything worse. If it was just a polyp, I would not worry.
If you still have doubts call whoever did the procedure and try to find out more info.