The heart has one way valves between each of its chambers so that none of the unoxygenized blood gets mixed with the oxygenized blood. The heart rate increases with exercise to provide the working muscles with extra oxygen. The blood flows out of the heart through arteries and into it through veins. The Drango changes its color to camoflauge itself and then it bask in the sun to get warm. When it wants to cool down, it changes its color to camoflauge itself and then it goes and lies down in the shade.
Liquid waste is put into the bladder.
When the bladder is too full it urinates. The Drango can see extremely well. It has large eyes with lots and lots of rods and cones. The Drango can detect motion because the electrical pulse that conveys the image the eye is seeing to the brain can turn off and on 200,000 times in one standard earth second. The Drango can also hear very well.