Fact 1: Vinegar can cause harm to the eyes. Fact 2: Eyes: The eyes and their surrounding area are the most fragile part of the face. Given the two facts above, what can cause harm to the most fragile part of the face?

Choose your answer from:
1). Pesticides
2). water
3). cloudy days
4). cigarettes
5). light touches
6). smoking
7). vinegar
8). viruses
The answer is:
7).