Which is absent in aqueous humor ?

Options

A. Carbon dioxide
B. Oxygen
C. Hyaluronic acid
D. Glucose.

Answer

To determine which substance is absent in aqueous humor, we can follow these steps:

### Step 1: Understand Aqueous Humor
Aqueous humor is a clear, watery fluid found in the eye, specifically in the space between the cornea and the lens. It plays a crucial role in nourishing the eye structures and maintaining intraocular pressure.

**Hint:** Think about the location and function of aqueous humor in the eye.

### Step 2: Identify the Components of Aqueous Humor
Aqueous humor is composed of various substances, including:
- Oxygen
- Carbon dioxide
- Glucose
- Amino acids
- Water
- Electrolytes

**Hint:** Recall the substances typically found in bodily fluids and their roles.

### Step 3: Analyze the Given Options
The question provides four options:
1. Carbon dioxide
2. Oxygen
3. Hyaluronic acid
4. Glucose

We need to identify which of these components is not present in aqueous humor.

**Hint:** Consider the common components of fluids in the body and whether they are essential for eye function.

### Step 4: Determine the Absence
From the information gathered, we know that aqueous humor does contain oxygen, carbon dioxide, glucose, and amino acids. However, hyaluronic acid is specifically mentioned as being absent in aqueous humor.

**Hint:** Focus on the unique properties of hyaluronic acid and its typical locations in the body.

### Step 5: Conclusion
Based on the analysis, the substance that is absent in aqueous humor is **hyaluronic acid**.

**Final Answer:** Hyaluronic acid is absent in aqueous humor.