I personally do not use index cards, but they could be used for getting a outline of what your essay will be and how it will be formatted. You want to get a basic "skeleton draft" going then you can fill the blanks in-between and adjust as you see fit. That's how I would personally use them, but it's really up to you! You can do everything from notes from research on them, to doing your frame on them.
Answer:
Fact- Butterflies use their feet to taste
Example- a memoir, such as Thoreaus’s Walden, is one type of nonfiction
Anecdote- At college, he often got lost on his way to class
Explanation:
No they also teach differently and instill different core values in their students but the extended school days and yet do play a rule as well.