Answer: corals, crabs, oysters and urchins
Explanation:
Answer: Mechanical Isolation
Explanation:
Mechanical isolation is a type of barrier that prevents the species that are closely related from mating with each other.
It is used in case of plants and animals(here beetles) in which the without compatible sex organs individual of different species will not be able to mate and produce offspring.
Thus, the correct answer is option C
Protoplanets are bodies or celestial objects which have the same size as the moon or a bit bigger. These bodies develop to eventually become planets. Therefore, the answer to this item is most likely letter D. outer planets.