<h2>
A) </h2>
to observe both solutions before the reaction
Answer:
it is magnesium hope it helps
While a covalent bond is relevant here since it involves sharing electrons between two atoms, I suspect you are talking about electronegativity. Electronegativity is the measure of a particular element's general affinity to attract a negative charge (i.e. electrons) towards its nucleus.
The correct answer is A.
Hunger, chemical imbalance, and blood levels are all internal issues. Cat dander on the other hand is not something the body creates or and is something in the environment.
Thus, your answer is A.