Consider the following cross:
parent 1: yytt
parent 2: yytt
using the rules of probability, determine the probability that the offspring will show yytt genotype?

1

8

1

16

1

2

The question is one of a dihybrid cross.

The picture that I attach below is a punnett cross of the parents (Yy Tt and  Yy Tt).  

So first you have to separate the two parents into gametes by pairing the alleles ( Yt , YT, yT, yt).  Then I crossed then with the punnett square and from that we see that there are two possible off spring that will would possess the genotype Yy TT (shaded gray in the diagram).

Thus the probability that a Yy TT offspring would be 2 out of 16
                   =   
                   =  
                   =   12.5 %

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.