Final answer:
Plant cells have a larger volume primarily due to a large vacuole that reduces cytoplasm volume, and also because they possess a cell wall and chloroplasts not found in animal cells.
Step-by-step explanation:
The reason plant cells often have a larger volume enclosed by the plasma membrane than animal cells is because plant cells contain a large vacuole that occupies most of the cell's volume, thereby reducing the volume of the cytoplasm. This vacuole is critical for maintaining the cell's rigidity, storing nutrients, and managing waste products. In addition, plant cells have a cell wall which provides structural support and protection, and they also contain chloroplasts necessary for photosynthesis, which are not found in animal cells.