Changes in stool color alone do not cause symptoms. The underlying cause of the change in stool color, texture, or form is responsible for any symptoms. Bowel movements are usually light to dark brown in color, and there is moderate variation among individuals with respect to stool color, quantity and form.
Plants in the Twilight Zone As the amount of light decreases, the size and complexity of plant life also decreases. So whereas there may be flowering plants growing in the entrance zone, the twilight zone is typically marked by mosses and ferns.
In the twilight zone, there are numerous animals that are black or red. At depth, these animals are not visible. The black animals absorb all colors of light available and the red animals appear black as well; there is no red light to reflect and their bodies absorb all other available wavelengths of light. Thus red and black animals predominate.