A conditional sentence is a sentence containing the word if.  There are three common types* of conditional sentence:   ...

Chemical changes make chemical reactions and the creation of new products possible. Typically, a chemical change is irreversi...

Definitions of each of the levels of organization in the human body are a click away...

There are three watersheds in Spain: The Atlantic watershed carries water from the rivers which flow into the Atlantic Ocean. ...

Matter is everything around you. Atoms and molecules are all composed of matter. Matter is anything that has mass and takes up space. I...