Vocabulary -- know what you are talking about

Concepts -- understand the big picture

Why are seaweeds different colors?
What is the most important difference between unicellular organisms and multi-cellular organisms?
What is vegetative reproduction?
Why do organisms grow more slowly in cold water?
How are holdfasts different from roots?
Why are there no plants on the deep ocean bottoms?
Why is the phytoplankton very important to aquatic animals?
Why is the phytoplankton very important to land animals?

Facts -- get the details right

How long ago did multicellular life appear on earth?
The water protected the earliest life forms from ___________.
Do underwater plants have flowers?  Why or why not?
What is the depth below which photosynthesis is impossible?
What is a zoospore?
What limits algae growth in the oceans?
Which color of light penetrates most deeply into the water?

Picture It!

Draw diagrams of three seaweeds showing different kinds of growth habits.  Draw the holdfast if the plant has one. 
Underneath each plant print the type of environment in which this type of plant grows. 
What feature of this plant is useful in its particular environment?