Final answer:
The main hazard of flying after scuba diving is the bends, caused by the formation of nitrogen bubbles in the blood, formally known as decompression sickness.
Step-by-step explanation:
The potential hazards of flying after scuba diving are primarily due to the way inert gases, like nitrogen, behave in the body under different pressures. The correct answer to the question regarding the hazards of flying after scuba diving is d) The bends, resulting from nitrogen bubbles in the blood. When a diver ascends, the pressure decrease causes gases dissolved in the blood to become less soluble. This can lead to the formation of nitrogen bubbles in the bloodstream if ascent is too rapid, a condition known as decompression sickness (DCS) or "the bends". To mitigate the risk of DCS, it is essential for divers to ascend slowly from depths and make decompression stops. If a diver were to fly soon after diving, without allowing the nitrogen to safely leave their body, they could increase their risk of developing DCS due to the lower air pressure in an airplane cabin.