Actually, it somewhat belongs to plant kingdom. But its way too primitive and don't exhibit many characteristics of a plants. That's why it is put under " Protista "
Kelp is a multicellular protists. It is a large brown seaweed that grows in shallow waters. It is rich in nutrients. It is typically found near the coastal regions all over the world. It produces a compound that is called as sodium alginate. It can be burned to obtain the soda ash.
