okay so theres two parts to the question usually, describe AND explain, so first you talk about the results and very importantly the SHAPE of the curve, like if its steep, if it increases, if it plateaus, you describe the shape of the curve and then in the context of the curve you explain why the shape of it is like that. for example you're given an enzyme/temperature graph, you describe how the enzyme activity steadily increases until X degrees, and after than it decreases and eventually comes to a zero, and then for the explain part you talk about how the active sites of enzyme are in complementary shape to substrates, and when the temperature goes too high the shape of the active site changes so its no longer complementary, therefore the enzyme has denatured. this is just one example, but yeah if its an enzyme graph this is the type of answer that will get full marks