More people
the population grows when a male and a female mate and have children and those children have children and so on
Competition
Competition
A population grows slowly in the beginning because of child mortality rates. Not all children are guaranteed a safe birth. In the beginning there may be more deaths with less people in the world. As the population grows and grows the mortality rates seem smaller because the population is larger.
The definition of population growth is an increase in the number of people who inhabit a county, city, state, country, or territory. It is when the population grows or increases by increments.
limited resources
If the population in the East grows too much, then soon there will be too many people. Some will have to move to the West so as the East population grows, the West population will have to grow too.
Because their population grows and their thing grows ;)
Malthus's theory of population argued that population grows at a geometric rate while food output grows at an arithmetic rate and that food scarcity was, therefore, inevitable.
Exponential
It grows larger and/or more complex.
exponential growth