i think that if you do as many sit-ups as you can in one minute that you will just be really sore the next day. And you might harden your belly a little bit.
He didn't do situps, silly!
Situps and holds are good. Do as many as you can in 2 minutes (for each), then a one minute break. Repeat 3-4 times.
500 situps burn 100 calories so you need to do more than 2,500
alot
if only for a minute don't worry about it
Many things happen in the world in one minute. People meet, people die, babies are born, people go hungry, and so on.
maybe
situps in a decline position situps towards left and right side leg raises for lower abs
The best abdomen exercises that provide the quickest results are good old fashioned situps. There are many different variations of situps that work different muscle groups. Try finding them in fitness magazines.
How many sit ups should a 12 year old be able to do
Somebody dies.
Your best bet is to do the situp properly without cheating or trying to get away with sloppy situps. The heavier you are the more calories you should burn with situps but it is very difficult to tell beyond that an exact number.