Other sites let you use the Google Authenticator app to generate the six-digit number. The app generates a different six-digit number for each connected site, and these numbers change every 30 seconds. With the app, you don't have to wait a few seconds to receive a text message.
Factors that cause population growth include increased food production, improved health care services, immigration and high birth rate. These factors have led to overpopulation, which has more negative effects than positive impacts. Keep Learning.
Objectives: 1  1. Distinguish between population size, population density, population distribution, age structure, and reproductive base. 2  2. Know how to calculate the net growth rate for a population, and how to graph the resulting numbers to produce a J-curve (worksheet) 3. Explain the factors that limit the biotic potential and carrying capacity of a population, including density-dependent, and density-independent limiting factors. 4. Explain how human population growth went from 1 billion in 1800 to 6 billion in 1999. Have a reasonable estimate of the population of the US and world. 5.