What three factors did malthus say were the key to limiting population size?

The three factors that Malthus had believed would be the limit of population size are the following;

-          War

-          Disease

-          Famine

As these three factors are likely to contribute for making the population deplete or lessen because it makes the people to have a less chance of living.

the effect of the ming leaders banning ships with more than two masts was that there was no further construction of ships masts, because there was a surplus. ming emperors disallowed foreign exploration