Multiple choice What is nephrostome? The main tubular part of nephridia The funnel-shaped inner opening of a nephridium that is lined with cilia and allows water and waste to enter from the body cavity The short and narrow tube where nephridial duct opens A large number of smaller nephridia Reveal answer Fill a bubble to check yourself B Correct answer Explanation Nephrostome is the funnel-shaped inner opening of a nephridium that is lined with cilia and allows water and waste to enter from the body cavity. It is the upper part of nephridia.