If there are 60 crayfish living in a pond that is 20 cubic yards, what is the population density?

Which of the following statements is true? 1. the mantle of the earth is made of solid nickel and iron. 2. the crust of the earth is made of solid nickel and iron. 3. the inner core is made of solid nickel and iron.

Which organelles are labeled d, and what is one feature that distinguishes them from the other labeled organelles chloroplasts the only organelles that produce sugars from sunlight mosomes, only found in animal and bacterial cells centricles only found in animal cells mitochondra, the only energo-generating structures found in cells

The image shows the evolution of a species of fish. a few fish from a population developed different social behaviors and evolved into different species. two fish according to the image, the fish underwent . 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 .