If you are 12 you should be able to do atleast 15 to 25, i hope this helps
To increase the amount of push ups one does, they can slowly increase the amount of pushups they do each day.
They exercise your arms and chest a bit, and they burn a tiny amount of calories.
That is an unreasonable amount of pushups to do in under a minute.
This answer is for Air Force only; the amount of push-ups and sit-ups you have to do depend on a few things. There are different standards to graduate from Basic Military Training than there are for "Real" Air Force. And from there are they broken down by sex/age/waivers.
Unless you are named Charissa, you should be able to do at least 5-10.
Every other day lots of pushups situps and masterbations
they take a grading. this is where a person has to display a certain amount of skills in knowledge, fitness and respect. the standard gets higher as the belts do. some of the things in a test would be: a certain amount of catas (a sequence of moves) a fitness test moving basics press ups all performed in front of the sensei (teacher) who says if they have passed or failed.
muscular strength
yeah
Strength is generally measured by the amount of repetitions of an exercise per minute (e.g. pushups per min, sit ups p/m).
magnitude
You'd have to do a MASSIVE amount of pushups to get your chest muscles to grow to that point. A far more probable reason is that you're simply putting on weight, and that your body is predisposed to store it subcutaneously in your chest area. Taking hormones can also cause growth there.