Final answer:
A rider should immediately seek medical attention for unconsciousness, severe bleeding, and difficulty breathing, as each can indicate life-threatening conditions requiring urgent care.
Step-by-step explanation:
A rider should seek immediate medical attention for all of the conditions listed: unconsciousness, severe bleeding, and difficulty breathing. Each one of these conditions can be life-threatening and require prompt medical care. Unconsciousness can happen due to various reasons, such as a head injury, and can quickly worsen without medical intervention. Severe bleeding can lead to circulatory shock, which is a critical condition where the body is unable to supply sufficient oxygen and nutrients to the tissues, leading to cellular death. Difficulty breathing can escalate rapidly, especially if caused by constriction and tightening of the airway or severe allergic reactions, leading to a swollen throat or the sensation of a lump that makes it hard to breathe. Signs like shock, a rapid pulse, dizziness, or lightheadedness accompanying these symptoms are also red flags that immediate medical help is needed.