Seaweeds belong to the algae family. They are plant like organisms that live in water. They vary in size from small cells to plants 60 metres long. Some are found in seawater and others in fresh water.
Seaweed grows, makes food and reproduces only when covered with water; some survive without water longer than others.
They use photosynthesis to produce food. They don’t have leaves, stems, or roots but have fronds (to absorb light and water), a stipe, and a hold-fast to cling to surfaces