40. Is seaweed a weed? What is it and how does it grow? 



Plants as useful as seaweed can hardly be considered weeds because 

 weeds are commonly defined as uncultivated (wild) plants that are use- 

 less, unsightly, and have no economic value. Seaweed is used as a food 

 by millions of people, particularly along the Pacific Coast of Asia; it 

 also serves as food for livestock. 



Seaweed has many other uses, for example, as fertilizer, medicines, 

 source of iodine, and ingredients used in preparation of bread, candy, 

 canned meat, ice cream, jellies, and emulsions. 



In the late 18th century seaweed was the primary source of soda until 

 other sources became more economical and practical. In these years, 

 thousands of tons of soda were derived from sea plants. 



Attached seaweeds grow only along the narrow border near shore. 

 Growth is depth limited because natural sunlight is needed for the 

 photosynthesis processes of the plants. 



S£A Lettuce 



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