Here's why:

* Parenchyma cells are the most common type of plant cell and are responsible for a variety of functions, including storage, photosynthesis, and secretion.

* Chlorophyll is the pigment that gives plants their green color and is essential for photosynthesis.

* While some parenchyma cells contain chloroplasts and participate in photosynthesis, others are specialized for different functions and do not contain chlorophyll. For example, parenchyma cells in roots, stems, and fruits are involved in storing nutrients, water, or other compounds and lack chlorophyll.

Other plant cells, such as collenchyma and sclerenchyma cells, also lack chlorophyll. These cells provide structural support to plants and are not involved in photosynthesis.