Drag each label into the appropriate position in order to identify where each secretion enters the gi tract

Which best describes the digestive system of arthropods? a incomplete, two openings b complete, one opening c two-way, one opening d one-way, two openings

What environmental cues and landmarks do the geese use to determine the timing and direction of their migration over the mountains? how do they find their way?

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?