Which of the following is true about vertical expansion during matches?

The assertion that robots may extend above 18 inches under certain conditions is correct. In competitive robotics contexts like FTC, there are often specific rules governing how and when a robot can expand vertically. Typically, teams are permitted to extend beyond a set height (like 18 inches) during certain phases of a match, such as during the endgame or when specific criteria are met regarding the robot's performance or game state.

This flexibility allows teams to strategically use their robot’s height in gameplay, enabling innovative designs that can add an edge during competitions. Understanding the context and conditions under which height expansion is permissible is key for teams in planning their strategies and ensuring compliance with the competition rules.

Other options do not accurately reflect the rules governing robot height. Robots are typically subjected to strict height limits to ensure fairness and safety, and any extension beyond specific limits is heavily regulated, emphasizing the importance of knowing the precise conditions that allow for such expansions.