i think that it is a generator
Surprisingly, nothing.
Without changing the characteristics of the light bulb, it's not actually possible to change the voltage without changing the current as well. When the voltage is increased, the current through the bulb has to increase as well in order to make it glow brighter.
I think it is their normal state
Both A, B, and C are found in the excretory system.
Myofibrils are in the muscle of the intestines, villi increase surface area of the intestine, and nephrons help to filter in the kidney. Osteoblasts are found in bone, so therefore is not part of the excretory system