I would say excretion since that means the process of expelling waste matter.
In the first image, those are fake ribs that are attached to the sternum through the costal cartilage
in the second image are real ribs since they are directly attached to the sternum
<h2>Scientist Observing changes </h2>
If the population of the species is significantly decreasing then the species could become extinct. The decline in population is due to some factors like less immigration, aging, and decreasing fertility rates. But the most is due to less immigration which causes to decrease population. The extinction of population can be prevented by some serious actions which should be taken government.
