Uv light is light that covers the electromagnetic spectrum from infrared to near-ultraviolet, or all wavelengths that are useful to plant or animal life
Human activity can affect the river ecosystems because first of all humans take the water and use it for themselves, they also pollute it, disturb the ecosystems and kill fish or oysters etc. in the ecosystems.
An animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in CELL TO CELL RECOGNITION.
Carbohydrates have diverse functions, one of their functions is that they serve as a recognition signal at the surface of cells.
Carbohydrates located on the surface of cells enable cells to recognize and communicate with one another.
You are testing for the presence of starch: Iodine dissolved in an aqueous solution of potassium iodide - reacts with starch producing a deep blue-black color. This reaction is the result of the formation of polyiodide chains from the reaction of starch and iodine.
