It means they may or may not have the same function but have similar structure depicting that the organisms may have had a common ancestor.
Because these smaller cells can access and pass through the membranes of the other cell membranes and permeable coverings easily and voluntarily unlike larger cells. It is also for efficient for these smaller and miniscule cells to penetrate and travel, delivering and transporting goods and materials such as nutrients, oxygen and waste throughout the body without consuming enough energy and conserving lesser space.
For simple reasons, they are faster, more efficient and consumes little space, and most especially depletes lesser energy.
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.