Answer:
This structure has not been highly beneficial for the organism
Explanation:
Vestigial structures are cells, tissues, and/or organs that have no apparent function. Vestigial structures are retained during the course of the evolution, but often they are degenerate and/or atrophied (due to disuse). In general, these structures are homologous to anatomical structures that play a specific role in evolutionarily related species. Some examples of vestigial structures include, among others, the presence of the appendix in humans and wings in flightless birds.
Oxygen-poor blood goes into the lungs and through the lung capillaries after leaving the heart. It does so to be oxygenated by the lungs. The oxygen in the lungs comes from the air we breath. Once the blood is oxygenated, it goes back into the heart, to be pumped back into our bodies for distribution.
Well to reabsorbed most of the water from the urine so that only small amount can be excreted. Desert animals need their water