At 0:59 it shows the mechanism then at 4:41 it shows another example of the mechanism. 

Our team just emailed you. The video you are looking for is the following:

Yes the formation of cyclopropanes is the same thing as cyclopropanation. Your lecture notes just show a more complex structure. But the overall concept is still the same, we start with an alkene and use a carbene to form the cyclopropane. 

At this time we don't have downloads of these reaction summaries but you can find the video review and reaction summaries of several functional groups here in the below video. Check the timestamps in the description for each reaction summary.

That would still be correct. Either answer, with or without the Hydrogens would be accepted.

For the study with us series, we do not have an answer key because the answers are shown in the video. You'll find timestamps to each question/answer in the description of this video. The purpose of this was so that students would watch the full video because there are several different tips/tricks Melissa shows throughout the video and we don't want you to miss that. 

kay Luffman No worries! Happy to hear it makes sense :) 

Sometimes you will hear these terms used interchangeably, this depends on your professor. But yes stating this is a ketal is correct.  

Anna Shaw There are more practice problems and a complex splitting video under this category: NMR