Sea level:
The level of the surface of the ocean 

Soil erosion:
The wearing away of the soil by wind or water. There is generally a lot of soil erosion along river beds and around coastlines 

Solar energy:
Energy captured direct from the sun

Solution:
A mixture made by dissolving a substance in a liquid, such as water 

Southern Hemisphere:
The area of the earth below the equator 

Species:
A species is a group of similar organisms/individuals having a common origin and the ability to interbreed freely with one another.

Stomata:
Tiny pores on the surface of plant leaves that can open and close to take in and give out water vapor 

succulent plants:
Plants that have thick, fleshy leaves or stems for storing water. Sometimes these plants leaves or so tasty they have to take steps to protect themselves. They have prickles on their leaves to prevent animals from eating them. Can you think of some prickly plants that grow in hot countries?