A phospholipid molecule has a head and two tails. The tails are found :

Options

A. at the surfaces of the membrane
B. in the interior of the membrane
C. spanning the membrane
D. both (a) and (b)

Explanation

### Step-by-Step Solution:

1. **Understanding Phospholipid Structure**: A phospholipid molecule consists of a hydrophilic (water-attracting) "head" and two hydrophobic (water-repelling) "tails." This unique structure is crucial for forming cell membranes.

2. **Phospholipid Bilayer Formation**: In a cell membrane, phospholipids arrange themselves into a bilayer. The hydrophilic heads face outward towards the aqueous environment (both inside and outside the cell), while the hydrophobic tails face inward, away from water.

3. **Location of Tails**: Since the tails are hydrophobic, they are found in the interior of the membrane. This arrangement prevents water-soluble substances from easily passing through the membrane, thereby maintaining the integrity of the cell.

4. **Conclusion**: Therefore, the correct answer to the question is that the hydrophobic tails of the phospholipid molecule are found in the **interior of the membrane**.

### Final Answer:
The tails are found in the **interior of the membrane**.

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