The cladogram of the kingdom Animalia shows the relationship of selected animals based on their shared anatomical features. The
black numbered squares represent features that are critical for forming each branch in the animal kingdom. Square one represents a dorsal nerve cord, which means the animals in all the branches have a dorsal nerve cord. Which numbered square would represent the trait "mammary glands?" A) 3 B) 4 C) 5 D) 6
The sponge-like structure, as well as the high salt content of water and the <span>ease of contaminating water contribute to the environmental stress on a coral reef.
