yes they can.
How much weight you can lose in a month by drinking water and doing crunches every night also depends upon other factors. These include you start weight, gender, age, diet, metabolism and how many crunches you do each night.
No
you cant. but you can get abs by doing bicycle crunches and regular crunches.
Yes, doing crunches will help with the overall conditioning of your body core - which is part of the driving force needed by your legs,
20 calories per 100 crunches, if you're doing them correctly.
By doing exercise and crunches
No, you will tone that specific area but you can not 'spot' lose weight by simly doing cruches. By doing crunches you may lose weight from any part of your body.
Not much burning of body fat or weight loss will occur by just doing 150 crunches per day. Reducing your calorie intake, moderately lifting weights in order to increase your metabolism, and participating in some regular cardiovascular exercise, will be more beneficial to weight loss than those 150 daily crunches. You will only see abdominal toning once some of the fatty abdominal layer has been burned- no matter how many crunches you do.
Doing crunches won't make you bloated, it will help burn belly fat and gain abs. Eating junk food will make you bloated and fat.
There is no known method to speed up your metabolism.
Not much, crunches are no big calorie burners. But the few calories burned depends on how your body is buildt, your age, your metabolism, how you preform the crunch and so on.
Doing crunches does not make you skinny. Eating less calories than you burn and being active (cardio exercise) will make you skinny.