[Campbell Biology P.745] Which of the following statements accurately describes a feature of... | Practice Question

Which of the following statements accurately describes a feature of planarian anatomy or physiology based on the provided figure and text?

  • A: The pharynx is primarily involved in eliminating undigested wastes through its tip.
  • B: The ganglia serve as the main sources of sensory input and are located near the posterior end of the worm.
  • C: Digestion in planarians occurs within a highly branched gastrovascular cavity, increasing surface area for nutrient absorption.
  • D: Planarians have a single, dorsal nerve cord running the length of their body for coordination.

Explanation

Option C is directly supported by the text: 'Digestion is completed within the cells lining the gastrovascular cavity, which has many fine subbranches that provide an extensive surface area.' Option A is inaccurate as the pharynx's primary role is food intake. Option B is incorrect because ganglia are at the anterior end. Option D is incorrect because planarians have a pair of ventral nerve cords, not a single dorsal one.