Answer: Hydra
Explanation:
The organism that is free living in the bottom of the streams and ponds is anchored. Hydra is a free living organism which is found in temperate regions .Hydra can be found in a variety of freshwater habitats.
They are sessile and live attached to the aquatic vegetation, stones and submerged woods.
They feed on small insects and small zooplankton in the water bodies. They are less than 15 mm in height and are usually green in color.