Explanation:

Following are the uses of Seaweeds:
The animals such as sheep, cattle, and horses that lived in coastal areas eat seaweeds. 
Seaweed can be used to produce ethanol, which can be mixed with petrol, or methane, the main component of the natural gas.
Extract of seaweed is often found on the list of ingredients on cosmetic packages, particularly in face, hand and body creams or lotions.However, the use of seaweeds themselves in cosmetics,
rather than extracts of them, is rather limited.
There are two main areas where seaweeds have the potential for use in wastewater treatment. The first is the treatment of sewage and some agricultural wastes to reduce the total nitrogen- and phosphorus- containing compounds before release of these treated waters into rivers or oceans.The second is for the removal of toxic metal from industrial wastewater.