Which of the following features is the primary basis of Modern Systematics?

Correct answer: Cell structure, internal anatomy, and evolutionary relationships

The correct answer is B: cell structure, internal anatomy, and evolutionary relationships. Modern systematics is the scientific study of biological diversity and the relationships among organisms. Older classification often depended mainly on visible external characters, such as shape or colour. Modern systematics uses several kinds of evidence together: cellular features, internal anatomy, physiology, developmental patterns, molecular evidence, and evolutionary history. This combined evidence helps scientists decide whether organisms share a common ancestor. A is incomplete because external morphology alone can be misleading; unrelated organisms may look alike. C is only one superficial character and cannot show complete relationships. D is incorrect because geographical size is not a general basis of classification. Memory cue: modern systematics looks beyond appearance and asks, “What evidence shows common ancestry?”