The carbon cycle. (Most likely, I'm unsure)
Answer:
c. remain constant.
Explanation:
The half life is defined as the time at which the reactant's concentration reduced to half.
The formula for the half life for a first order kinetic reaction is:

Where,
is the half life
k is the rate constant.
<u>As seen from the formula the half life for a first order reaction is independent of the reactant's concentration. </u>
<u>So, it will remain constant on any change of the reactant's concentration.</u>
<span>If a psychoactive substance is used or abused over a long period of time, a person may be unable to function properly without it. An abuser can suffer extreme withdrawals.</span>