People having sex.
In my point of view the main reasons of population growth is poverty and illiteracy.
population growth
The organism size growth rate population density
Australia's main challenge is sustainable growth. Most of the country/continent is quite arid. It will need more and better water desalination plants for drinking and desert agriculture if it is to maintain significant population growth. Desalination plants are already in use near coastal population centers. Another challenge is exports. Aside from a wealth of mineral exports, Australia doesn't have a large, diversified established production capacity like that of the U.S. or the European Union, owing to the small population and small built environment.
it helps rapid population growth decrease
The main components of population growth are birth rate, death rate, immigration rate, and emigration rate. Birth rate refers to the number of births in a population, while death rate reflects the number of deaths. Immigration rate is the influx of individuals from another population, while emigration rate is the outflow of individuals from a population. These components together determine the overall growth or decline of a population.
Australia's capital city is Canberra.However, its largest city by population is Sydney, the capital of New South Wales.
industrialist and immigrants.
The industrial revolution. Factories and manufactures were located in the large cities, so the workers moved from the rural areas to the cities for jobs, therefore, population increase.
Most probablly because of Edward Hammond Hargrave who claimed to find gold in Australia. That's how the gold rush started which increased Australia's population by more than double the amount of people before the gold rush.
The industrial age.
Increased birth rate and decreased mortality rate.