Students examined two plants - one healthy (Plant A) and one neglected (Plant B). They observed that Plant A was green while Plant B was brown. The investigation showed that Plant A, which was near a window, received sunlight while Plant B did not. Students then felt the soil and found Plant A's soil was damp while Plant B's was dry, indicating plants need water. The document concludes that for plants to thrive, they need sunlight, water, and rich soil.