Answer:
Echinoderms have a calcium carbonate endoskeleton, and vertebrates have a bony endoskeleton made of calcium phosphate. have bones mostly made of calcium phosphate.
Explanation:therefore, echinoderms do not have true endoskeletons.
The answer is
ocular lens
Stage
Objective lens
Focusing le s
Without variation in traits among the population, there would be no variation in the relative fitness of individuals within the population (i.e. (higher level) no differential reproductive success between individuals). Without varying reproductive success between individuals in population based on traits, there will be no change in frequency of traits in the population over time. To put it simply, there is nothing for natural selection to act upon.
