Answer:
C, a long absolute refractory period.
Explanation:
Tetanus is not possible in cardiac muscle tissue because cardiac cells have longer action potentials and a very long refractory period compared to other cells. This helps prevent the heart from cramping and seizing up.
The phenotype is just a characteristic/trait.
For instance Brown and Green are phenotypes of eye color.
This can also be used in Punnet Squares, and could be displayed as B and G.
B equaling dominant Brown, and G = dominant Green, vice versa to g and b where they are recessive.
You can not worry about being shocked due to the cord being insulated not allowing the voltage to go through you but the cord
B .............................................................................
If the pH/temperature fluctuates, the enzyme conditions would no longer be favorable, meaning the enzyme would no longer be able to perform its assigned function. If the conditions become too unfavorable, the enzyme would change shape (denature).