It means not to get too invested in details or to become so invested in something that you can’t focus on anything else.
Step-by-step explanation:

I hope I'm correct. I've never learnt differentiation for log and exponents before
Increasing on:
(−∞,1)
Decreasing on:
(1,∞)
Im pretty sure it’s All students in each grade because it says she wants the sample from the ^entire^school