Density is measured in mass per volume thus C would be the answer.
2.17 g / cm³
The right answer for the question that is being asked and shown above is that: "a decreasing number of viable, fertile hybrids is produced over the course of generations." The phenomenon of fusion is likely to occur when, after a period of geographic isolation, two populations meet is that <span>a decreasing number of viable, fertile hybrids is produced over the course of generations.</span>
A shield vol may be produced by hot spots which lay far away from the edges of tectonic plates. Shields also occur along the mid-oceanic ridge, where sea-floor spreading is in progress and along subduction related volcanic arcs.
Its called the extracellular matrix