According to the image, the fish underwent sympatric speciation. The new species of fish had mating seasons that were different from that of the original fish. Because of the differences in mating seasons, the fish underwent reproductive isolation. This mode of isolation would be temporal.
Sympatric speciation happens within a population of an organism that gets isolated reproductively due to differences in their mating periods. This time dependent isolation is called temporal isolation. Example, a fish population can split into two if some of the fishes start mating early in the spring while the rest mate late in the autumn. The spring-mating population will not become compatible to mate with the late-autumn-mating population.
The correct answer is - Most killer whales congregate in the areas that are near the Arctic/Antarctic Circles.
The killer whales have a very large distribution, and they can be found in all oceans, apart from the Southern Ocean. It is noted though that the population density of the killer whales differs from place to place. The higher concentrations are found around the Arctic and Antarctic Circles, where there's cool rich waters, while in the lower latitudes they are much rarer. The reason for this probably lies in the fact that most of the animals that are considered to be the prime food source of the killer whales are living in this rich cold waters.
Phylum, it is the second largest group.
