Which sentence uses an appropriate transition to add additional support for a main idea? 1. Thorough hand-washing prevents illness by killing germs on the hands; and yet, cleaner hands are less likely to spread contamination to other surfaces.

2. Thorough hand-washing prevents illness by killing germs on the hands; thus, cleaner hands are less likely to spread contamination to other surfaces.

3. Thorough hand-washing prevents illness by killing germs on the hands; in addition, cleaner hands are less likely to spread contamination to other surfaces.

4. Thorough hand-washing prevents illness by killing germs on the hands; in summary, cleaner hands are less likely to spread contamination to other surfaces.