Final answer:
The height of the cork above the sea floor can be represented by a sine curve. At point a, the cork is at its highest point, not moving upwards or downwards. At point b, the cork is at the midline of its motion, moving downwards. At point c, the cork is at its lowest point, not moving upwards or downwards. At point d, the cork is at the midline of its motion, moving upwards.
Step-by-step explanation:
The graph of the height of the cork above the sea floor as a function of time can be represented by a sine curve. At point a, the cork is at its highest point, where the height is maximum and it is not moving upwards or downwards. At point b, the cork is at the midline of its motion, moving downwards. At point c, the cork is at its lowest point, where the height is minimum and it is not moving upwards or downwards. Finally, at point d, the cork is at the midline of its motion, moving upwards.