Which of the following are recognized physical signs of stress?

The correct choice identifies physical manifestations of stress, emphasizing that physical symptoms can arise in response to stress. While paralysis of limbs is not a recognized symptom of stress and does not typically occur, both frequent urination and trembling are indeed noted reactions that can result from the body’s stress response. Under stress, the body triggers the "fight or flight" mechanism, which can lead to these physical reactions as it prepares to respond to perceived threats.

Headaches and fatigue, as well as anger and irritability, while relevant, are not strictly categorized as physical signs; they are more often considered emotional or psychological responses to stress. Isolation and avoidance also pertain to behavioral responses rather than physical signs. Therefore, the choice highlighting trembling and frequent urination correctly points to specific physiological responses, though it's important to note that paralysis does not fit within the context of stress symptoms.