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.
The sunlit zone is home to a wide variety of marine species because plants can grow here and water temperatures are relatively warm. Lots of marine animals can be found in the sunlit zone including sharks, tuna, mackerel, jellyfish, sea turtles, seals and sea lions and stingrays. There are not a lot of places to hide in the sunlit zone! Some species have an adaptation called countershading.