Explanation:
Population is a dynamic thing and is affected by many internal and external factors. When we do population estimation, we mainly do it based on statistics. We note the past trends of population growth and try to predict the future size of the population at the same rate of growth. We can not take into account all the factors that affect the growth rates at different manner. When the population is growing, its characters are changing constantly and thus it follows different rates of growth at every moment. Final size of a population is the total summation of these different rates of growth acting upon different sizes of population.
One of the most significant impacts of the increased use of chemical fertilizers, herbicides, and pesticides is dramatic increase in production.
Answer:
folllowing convection patters similar to those of winds, ocean currents, both near the oveans surface and far below it, carry warm water from the tropics to the poles. other currents return cold water to the equator.
Explanation:
Answer:
Scientists use models to help them understand and explain ideas. Models explain objects or systems in a more simple way. Models often only show only a part of a system. The real situation is more complicated. Models help scientists to make predictions about complex systems. Some models are something that you can see or touch. Other types of models use an idea or numbers. Each type is useful in certain ways.
Explanation:
Physical Models
A physical model is a representation of something using objects. It can be three-dimensional, like a globe. It can also be a two-dimensional drawing or diagram. Models are usually smaller and simpler than the real object. They most likely leave out some parts, but contain the important parts. In a good model the parts are made or drawn to scale. Physical models allow us to see, feel and move their parts. This allows us to better understand the real system.
Answer:
A
Explanation:
Wind currents send air pollution from one continent to the next.
When air rolls or wind current, it picks up more smog and dirt from air peppered with thunderstorms that help bring the pollutants miles above the Earth's surface. This occurrence has made researchers to better understand how high levels of ozone occur off the west coast of Africa, far from known air pollution sources.