Choose your answer from:
1). unknown;
2). safe;
3). threatened;
4). harmful substances;
5). Pollution;
6). foreign;
7). barrel-shaped;
8). contaminated;

Fact 1: Scraping oneself on a contaminated object may cause infection. Fact 2: An infection is an invasion of the body by bacteria. Given the two facts above, scraping oneself on an object that is what, may cause an invasion of the body by bacteria?
Answer:
8).