Final answer:
The correct answer is c) Cell wall, as it serves a protective and structural role for the plant cell, much like bark does for a tree.
Step-by-step explanation:
The correct answer to the analogy Bark is to tree as __________ is to plant cell is c) Cell wall.
Bark serves as a protective outer layer for trees, similarly, the cell wall is the rigid outer layer that provides protection, structural support, and maintains the shape of the plant cell. In contrast, the cytoplasm is the gel-like substance within the cell membrane, chloroplasts are the site of photosynthesis, and vacuoles store nutrients and waste products in the cell. The cell wall is the most analogous to bark in this context as it serves a protective and structural role for the plant cell.