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.
Animals in the Sunlight Zone Animals in the Twilight Zone Because of the small amout of sunlight animals that live in this layer have to be able to survive colder tepuratures. Also, because of the lack of sunlight plants can not live in this layer.