Here is another one:

"The interval between two events is the ______________."

I would depend on the specific context of that interval. Looking up "interval" on the online thesaurus, I found:

pause, hush, lapse, letup, suspension; interlude, intermission; recess, respite; wait; break, gap, interruption.

Which science are you asking about? Do any of those fit?

I hope this helps. Thanks for asking.

i need help with electron

"The interval between two events is the duration of time elapsed between them."