The example of a civic life activity is voting in an election. To determine the answer, we can look at the options given and identify which activity fits the criteria of a civic life activity. A civic life activity typically involves actively participating in the community and contributing to society. From the options provided, borrowing books from a library and planting trees in your yard do not directly involve community participation or contributions. On the other hand, joining a sports team can be seen as a form of community involvement, but voting in an election is a clear example of civic participation. Therefore, the correct answer is voting in an election.
The example of a civic life activity is voting in an election.
