When we look at different environments on the Earth we find areas that have to do with the ocean, or
(4) areas. By contrast, (5) areas deal with
dry land and are higher toward the coastline. Both of
these areas are a part of the (6) __, which is the
portion of the coastline that goes through periods of
coverage and exposure due to the changing ocean
level. This pattern of ocean water rising and falling is
called the (7)
___. It is caused by the (8) . of
the Moon and the rotation of the Earth.