What vitamin is involved heavily with the replacement of red blood cells and digestive tract cells?

The answer to this question is folate.

Folate is also known as folic acid and vitamin B9. This vitamin is used to cure anemia which is caused by deficiency of folic acid. This is also used by pregnant women to make the baby healthy by drinking vitamins and milk to increase folic acid in the body. 

No because the eaeht is on a 23.5 degree axis tilt and so when it is winter the northern hemisphere is pointing away from the sun and the soutubern hemisphere is pointing toward the sun

Atp is is our little "pocket" of energy. of course, if you have too little, then it means you have too little energy, and you'll pass out. the way to not have enough, is to have no energy sources (glucose, fats, proteins). you can't have too many atp molecules. cycles like the krebs cycle produce it, but if you have too much of any substrate (or too little for that matter), the cycle stops and atp is no longer made (it stops until substrate levels are such that the process can go on). in any case, this is unlikely since atp is constantly hydrolyzed and remade, even while you're asleep. you won't have too much. if you have zero, you are dead or dying.