• How do plants colonize bare ground?
  Some plants can quickly colonize bare soil. They do this by ...

• What is a Joshua tree?
  The Joshua tree grows in the Mojave Desert, California, USA. It grows ...

• How do plants make the soil more fertile?
  When plants die, they decompose, releasing the chemicals in their ...

• Which is the hottest desert?
  Parts of the Sahara and the Mojave Desert in North America experience ...

• How are plants used to clean up sewage?
  Sewage works use tiny algae and other microscopic organisms in their ...

• What is an oasis?
  An oasis is a place in the desert where water is in plentiful supply, ...

• How do plants recycle water?
  Plants help to return water to the air through the process of ...

• What is the nitrogen cycle?
  Bacteria in the soil use nitrogen from the air and turn it into a ...

• How can plants be used to help stop erosion?
  Erosion is when soil is loosened and removed by the action of natural ...

• How many seeds can a plant produce?
  In the tropical forests of Central and South America, a single ...