For most organism (animals and humans) glucogen is stored in the liver. Glycogen in basically a bundle of glucose. This is like storing energy as the glucogen can be changed back into glucose by a hormone by Glucagon. It breaks down the insoluble glycogen into glucose that can be used in respiration which creates energy.
Respiraton
Glucose+ Oxygen = Water + Carbon Dioxide + ENERGY
On my work the answer was D ..
I think I understand even without the picture. I'll add a picture of the Punnett Square filled in, but what you're crossing is
Tt x tt (heterozygous crossed with a homozygous recessive)
The ratio you get in the end is 2 heterozygous (Tt) and 2 homozygous (tt) offspring, so the ratio is 1:1.
So the percentage of offspring that are homozygous recessive is 50%.