Speaking politely is an example of which social skill?

The correct answer is that speaking politely is an example of tactfulness. Tactfulness involves a sensitivity to how one's words and actions may affect others. It ensures that communication is considerate, kind, and chosen carefully to avoid offending or upsetting others. This skill is vital in a veterinary assistant's role, as interactions with pet owners and colleagues alike should be handled with a level of respect and awareness of feelings.

While the other options represent important social skills in their own right, they do not specifically capture the essence of communicating politely. Civility relates more to general courteous behavior, assertiveness focuses on expressing one’s own needs and desires in a confident manner, and humor involves using wit or jokes in communication, which may not always be appropriate in sensitive situations. Hence, tactfulness best embodies the principle of speaking politely.