Kelp, which is commonly described as a type of seaweed, is a diverse group of marine algae with about 112 species and a part of the large kingdom of life known as the protista, which are mostly single-celled organisms. Kelp resembles plants because it uses photosynthesis and has structures that resemble their stems, roots and leaves. However, it differs from flowering plants in that it has a simpler structure, lacks tissues to transport water and food from one part to another, and has an amazing ability to flourish in conditions that are much too harsh for plants.
Kelp is by far the largest protist in size, with giant kelp, the largest species, attaining heights of about 30 meters on average but sometimes more than 50 meters. It grows at an average rate of 28 centimeters per day but can grow by more than 60 centimeters daily in ideal conditions, which is even faster than bamboo. Kelp is widely distributed along cool, shallow and nutrient-rich ocean coastal waters with sufficient sunlight for photosynthesis in the temperate and subpolar regions. It forms dense kelp forests that provide crucial habitat for thousands of other marine species.