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 between the euphotic and the bathyal zone is the twilight zone, an area that still receives some sunlight, but not enough for plants to grow. The bathyal zone (aka midnight) is the middle zone that has no light. Many zooplankton and smaller fish live here.he euphotic zone is from the surface of the ocean down 200 meters. This zone is also sometimes called the sunlight zone because there is enough sunlight to have photosynthesis. This zone has the highest levels of sunlight, photosynthesis, and dissolved oxygen. Many large predatory fish live here.