Which of the following are types of diving emergencies?

The correct choice identifies arterial gas embolism and decompression sickness as types of diving emergencies because they are conditions directly related to physiological changes that occur during scuba diving activities.

Arterial gas embolism happens when gas bubbles enter the arterial bloodstream due to rapid ascent or lung over-expansion, leading to serious complications as these bubbles can obstruct blood flow and cause organ damage. Decompression sickness, often referred to as "the bends," occurs when a diver ascends too quickly and nitrogen that was dissolved in body tissues and blood forms bubbles, resulting in issues like joint pain, neurological symptoms, or even life-threatening conditions.

Both conditions are specific to diving and its related activities, directly linking to the risks associated with pressure changes encountered underwater.

Other options, while concerning health issues, pertain to different emergencies not specifically related to diving. Hypoxia and hypercapnia, for example, refer to oxygen deficiency and excess carbon dioxide in the body, occurring in various environments, not exclusively underwater. Heat stroke relates to environmental conditions affecting body temperature, while shock and near drowning encompass emergency responses in various situations, including but not limited to water-related incidents.