Anxiety is primarily characterized by:

Anxiety is primarily characterized by a feeling of worry or nervousness. This feeling is often accompanied by physical symptoms such as increased heart rate, sweating, and restlessness. Anxiety can manifest in various situations, often leading to excessive concern about future events or potential outcomes. This chronic worry can interfere with daily activities and overall functioning, making it a central feature of anxiety disorders.

In contrast, the other options describe feelings or states that do not align with the definition of anxiety. For instance, a persistent feeling of fatigue may relate to conditions such as depression or chronic fatigue syndrome, while a sudden onset of happiness is not associated with anxiety at all. Additionally, a lack of motivation to engage in activities is more indicative of depressive disorders rather than anxiety itself.