Mutations occur at low rates. They are rare and not very common in most individuals. This explains why the process of evolution and adaptation occurs over long periods of time. 

The use of child laborers leads to higher birth rates. More children are needed to support families and households. Educating women also decreases birth rates. This is the reason why developing countries tend to have higher birth rates than developed countries. A lower average marriage age leads to an increase in birth rates. Religion can influence birth rates, either raising or lowering (generally it raises the birth rate).

Corals are r-selected species, categorized by producing many offspring at once, which individually have low chances of survival, and short lifespans. Other r-strategists include rodents, insects, and other small-bodied, early-maturing animals. K-selected species produce few offspring and invest lots of parental care to ensure a higher chance of survival. Humans are an example of a K-selected species.

Elephants are large-bodied and give birth to only one offspring every few years, and mothers have a large role as caregivers to ensure the survival of their young. The other species listed here are r-selected species and have many offspring at a time. In some cases, r-selected species do not parent. In others, offspring mature very quickly and parents do not have to provide care for very long.

The correct response is density dependence. Since the population growth rate is dependent on the size of the population, it is therefore regulated by density. This is the perfect example of a density dependent population. 

The correct response is density independence. The leafhopper population was not regulated by density. The only thing that regulated the population was abiotic events, such as forest fires. 

In terms of population trends, Nigeria can expect to see exponential growth in the following years for two reasons: Fertility rates are already quite high (e.g. a stable population is at  births per female) and a large portion of the population is under the age of fifteen. Present fertility rates ensure current exponential growth, while a large proportion of the population reaching reproductive age ensures future population growth, especially if the fertility rate remains inflated. 

Often, the growth of cities is too fast for the construction of adequate infrastructure. This results in transportation problems, including traffic gridlock and longer commuting times. The other answers are true regarding urbanization. Cities have a number of environmental drawbacks and benefits.

Ukraine, like many former Soviet Bloc countries, has a declining population due to political unrest. Nigeria, the Philippines, the United States and India all have increasing populations.

In the first stage of a demographic transition, a population has a high birthrate, a high death rate, and a stable population. Technological development is low, and populations are controlled mainly by famine and disease.