Are there any free programs that let's you use the greenscrene? but, inside already made videos not while making the video.

The programs I know that let you use the GreenScreen on already made videos is imovie and SonyVegas Pro. I know how hard it is to find friendly opinions from others so they can help you when trying to find Edit related programs for pictures and videos. I hope this helped.   

Wifi router/

For question 1, i'm a bit stuck between serif fonts or large enough type to read. serif fonts are good fonts to use because their easy to read. but you also need your type be large enough to read. if i had to say what you need to consider most important, i would say d is the answer.  for question 3, i believe the answer is d. it seems most appropriate to do that. on every page or every other page would be too much, and only on the contact page just seems inappropriate.  for question 4, it's probably a. by "color scheme" it doesn't mean just one color, but a set of colors. colors that are complimentary to each other. having too many is too distracting so it's best to limit it as much as possible, but not to the point where your website looks dull.hope this !