In biology, the vertical scale describes the _______, and the horizontal scale describes the _______.

Erwin Chargaff found that in DNA, the ratios of adenine (A) to thymine (T) and guanine (G) to cytosine (C) are equal. This is the best example of study at the _____ level in life's hierarchy.

Using a mudcrab as the sample organism living in a mangrove ecosystem, identify which of the following images illustrates the correct biological hierarchy.

Groups of different species residing in a given area are referred to as