An average student remembers about 50 percent of a ten-minute lecture when tested (2)immediately; and 25 percent of same lecture when testd fifty-five hours later.

Question

(2)
a)No change
b)immediately -- and
c)immediately and

I chose answer c) since I didn't think a comma was necessary in this case.
thanks

Answer 1

Where are the instructions of what you are eactly to do"

Sra

Answer 2

You're right. The comma is unnecessary.