Hi. I have a question about using modules.

Doesn't look that way to me :)

Do modules have the tendency to slow down programs?

No, of course not; at least not any more than "programs" have a tendency to slow down "themselves"

Or are they efficient in that way.

What is "that way" and what does "efficient" mean ^(*)?

Or does that depend on individual cicumstances?

No, it depends on algorithms and circumstances (hardware)

Do you know what is a module? ^{( * * )}