Figure 8 shows how the rate of photosynthesis changes with light intensity. Which part of the graph could be represented by the equation y = mx + c ?

The equation y = mx + c describes a linear relationship, which is represented graphically as a straight line. * **From 0 to 5 000 lux:** The graph is a straight line passing through the origin. This indicates that the rate of photosynthesis is directly proportional to light intensity. Light is the limiting factor here. This section fits the equation y = mx + c (with c=0). * **From 5 000 to 20 000 lux:** The graph starts to curve. This means the relationship is no longer linear; the increase in rate is slowing down as another factor (like CO₂ concentration or temperature) starts to become limiting. * **From 20 000 lux onwards:** The graph becomes a horizontal line (a plateau). Here, the rate of photosynthesis is constant and does not increase with light intensity. Light is no longer the limiting factor.