The size of a population can get larger with no influences from migration if birthrate _ or death rate -

The size of a population can get larger with no influences from migration if birthrate increases or death rate decreases.

Explanation:

A population tends to gain individuals by increased birth rate and immigration and lose individuals by death. The total number of births every 1,000 in a population in a year or period is called as the birth rate.

The population growth is measured using the birth rate, migration rate and the mortality rate. Therefore, the size of a population can still grow with no or minimal influence from migration if the birthrate increases or death rate decreases.