**Core Concept**
Anxiety is a complex psychological and physiological state characterized by feelings of fear, apprehension, and unease. It is often associated with increased sympathetic nervous system activity, leading to various physiological changes. Understanding the pathophysiology of anxiety is crucial in identifying its manifestations and distinguishing it from other conditions.

**Why the Correct Answer is Right**
Anxiety is commonly associated with symptoms such as palpitations, tremors, and muscle tension, which are a result of the increased sympathetic nervous system activity. This is mediated by the release of catecholamines, such as adrenaline, which acts on beta-adrenergic receptors in the heart, leading to increased heart rate and contractility. Anxiety can also lead to respiratory changes, including hyperventilation, which can result in respiratory alkalosis.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as anxiety is indeed associated with increased heart rate and palpitations, which are classic symptoms of anxiety.
**Option B:** This option is incorrect as anxiety can lead to respiratory changes, including hyperventilation, resulting in respiratory alkalosis.
**Option C:** This option is incorrect as anxiety is commonly associated with symptoms such as tremors, muscle tension, and restlessness, which are all characteristic of anxiety.

**Clinical Pearl / High-Yield Fact**
A key feature of anxiety is the presence of respiratory alkalosis, which can be a useful diagnostic clue in differentiating anxiety from other conditions. Additionally, the use of beta-blockers, such as propranolol, can help alleviate some of the physical symptoms of anxiety, such as tremors and palpitations.

**Correct Answer: C. Increased appetite is not typically seen in anxiety; rather, it is often associated with decreased appetite.**