Concept:Malthus described positive checks as natural factors like famine, disease, and war that raise the death rate.
Explanation:Positive checks occur when population grows faster than food supply.
They increase the death rate.
Malthus believed these checks could be avoided if people voluntarily controlled population growth.
He called this “moral restraint”, which means practicing self-control and postponing marriage.
Among the given options, adopting more restraint is the preventive measure.
Building more hospitals or reducing death rate would not prevent the root cause.
Answer:D. More restraint is adopted.