Place either affect or effect into the gap. As affect is a verb, in some cases you may have to change the form i.e. affected; affecting.
Note: Don't use capitals and don't leave a gap after the word. If you do it will be marked wrong.
The robbery had a very bad
on the family.
The strong light has
Rising sea levels are
What kind of
do you think lowering the pass mark will have on the students?