What is the primary function of chlorophyll in plants?

The primary function of chlorophyll in plants is photosynthesis. Chlorophyll is a green pigment found in the chloroplasts of plant cells, and it plays a crucial role in the process of converting light energy into chemical energy. Through photosynthesis, chlorophyll absorbs light, primarily from the blue and red wavelengths of the spectrum, and uses this energy to convert carbon dioxide and water into glucose and oxygen. This process not only provides food for the plant but also releases oxygen into the atmosphere, which is essential for the survival of aerobic organisms, including humans.

The other options relate to processes that, while important for plant life, do not directly involve chlorophyll. Water absorption is facilitated by roots and does not require chlorophyll. Root development is concerned with the growth and structure of roots, again unrelated to chlorophyll's function. Respiration is the process by which plants convert glucose into energy, and although it occurs in plant cells, it does not directly involve chlorophyll. Thus, the unique ability of chlorophyll to capture light energy and drive photosynthesis makes it essential for plant growth and the ecosystem as a whole.