Native English speakers, can you help me understand a few words in this context?

I highlighted what I didn’t get, 1) what does SNAPSHOT mean here? Is it like quick overview of? Or a scene? 2) wha does “ the usual range of students needs”; does the wittier mean that usually there are different needs for each students but in Simmon’s case the needs are just too different? 3) what does the long hyphen mean? Does it mean “like...”? Thanks A LOT in advance.
Answers

Mackenzie

1) Quick overview-- a brief look. 2) 'more than the usual range of student needs' means that this teacher's students are more diverse in their needs than you find in the average class. 3) it's an em dash, in this place it takes the place of putting the list of science supplies within parenthesis.

Anonymous: More than the usual range of student needs

More than the usual range of student needs: can refer to physical or emotional disabilities, distractibility, learning styles, difficult home situations, or even conditions such as asthma. This is a very broadly inclusive term.