Can I walk all day to lose weight?

I think much have already being said to answer your question. Let me just add that, Yes walking can, undoubtedly, help lose weight. But there is no point wanting to do it all day. Walking at a continuous pace will not only help you lose weight but boost your energy levels too.
Walking should be aimed at particular distance or duration covered to maintain the proper health and control weight.
It is always necessary to maintain good walking style to get the maximum benefits of this exercise and at the same time minimizing any health risk.
The following walking styles should be maintained for obtaining the benefits.
• Try to be as straight as possible including back while walking.
• Your arms should be swing in front and back straight at a maximum angle of 90 degree centigrade with the body.
• Take more steps per minute instead of taking longer steps.
• Walking should be maintained in a straight line as possible and try to keep your foot very close.
• Try to breath deeply.
• You should start walking slowly in initial days and increase the speed and miles gradually as you proceed, keeping in mind your body's response
 to these exercises.
I believe with this tips and the others given here you can kick-start your weight loss journey.
Can old people tell how old other old people are?

No. No more than any other singled-out group can.(At least not without checking their AARP membership card.)Age determination depends on lots of things, including the relative health, attitude, and mental state. There are 80 year olds who seem 60 and 40 year olds who look 60 and 20 year old crack heads who look 50.

Can we get a flat belly just by running every day, without doing any crunches?

If you're trying to get rid of stubborn belly fat, you might wonder whether running is the solution. Unfortunately, while running is a great way to burn calories and lose overall weight, it's not a guaranteed way to lose your spare tire, belly, pooch, or whatever else you want to not-so-affectionately call it. It's

How to get a six pack or possibly an eight pack

Decrease your body fat percentage to the appropriate level. For women, it's usually 12–16%. For men, it's usually 6-11%.Work your core twice every 6 days. Do planks, dumbbell crunches, weighted supine leg raises, body twists, incline sit-ups, ab wheel rollouts, stomach vacuums. Try to