_________ is water released from clouds in the form of rain, freezing rain, sleet, snow, or hail.

The water on our planet is the same water that was here millions of years ago. However, it is continuously moving and being recycled through the water cycle.

_________ is the process of water vapor turning back into a liquid upon cooling.

The evaporation of water out of the leaves of plants happens during which step?

The image shows various stages in the water cycle. During which stage does water flow back towards the sea as runoff?

If the plant population decreased, the amount of carbon in the atmosphere would _________.

When humans burn fossil fuels, most of the carbon quickly enters the as carbon dioxide.

Identify the cycle illustrated in the diagram.

Large areas of land are being developed. In the process, thousands of trees are being removed and burned.

Yes or No: When forest are cleared or burnt, stored carbon dioxide is released into the atmosphere and this would affect the carbon cycle.

Which of the following processes in the nitrogen cycle is where decomposers break down animal and plant proteins (from dead organisms) and waste to release energy, releasing a form of ammonium into the soil.

Humans add nitrogen to the nitrogen cycle by -

What is the most abundant gas in the atmosphere?

How do animals get the nitrogen they need?

Organisms that need nitrogen to survive.

What is the main reservoir of nitrogen?

What type of growth is demonstrated in the graph?

Leveling off of the population after the maximum number the environment can support has been reached.

Which of the following would likely be a limiting factor to a population?

When rabbits were introduced to Australia, they began to breed exponentially. However, over time their population has begun to decrease due to a limiting factor.

What is most likely the limiting factor in this situation?

Which of the following demonstrates population growth when there is limited available water in an area?

Habitat availability increases for a population. How would the carrying capacity of the prey change?

What happens if a population grows past its carrying capacity?

This may cause a population to increase

Something that regulates the size of a population is called...

What is the carrying capacity of the graph?

What is the carrying capacity of the graph?

If a disease destroying barley plants in a field swept through an ecosystem, what would happen to the barley-eating bird population in the the field ?

A scientist was studying a population of fish in a pond over a period of 10 years. He observed that the population increased each year for 3 years, and then remained nearly constant for the rest of the study. The best explanation for this observation is that the population had