National League for Nursing (NLN PAX) Practice Exam

Photosynthesis primarily occurs in the leaves of a plant, where specialized cells known as chloroplasts contain the pigment chlorophyll. Chlorophyll is crucial because it absorbs sunlight, specifically capturing light energy to convert carbon dioxide and water into glucose and oxygen. This process is fundamental for the plant's energy production and growth.

While roots, stems, and flowers play important roles in a plant's overall structure and function, they do not participate directly in photosynthesis. Roots are primarily responsible for water and nutrient absorption from the soil. Stems act as conduits for transporting those nutrients and water throughout the plant and providing structural support. Flowers are primarily involved in reproduction and do not play a significant role in energy production through photosynthesis. Therefore, the leaves are the correct answer as they are the main sites where sunlight absorption for photosynthesis takes place.