What does a straight line represent on a distance vs time graph?

It represents the relationship between the distance travelled and time spent as constant or at a stop.

Explanation:

This is because as the line progresses, the time increases the distance should change as well my moving up or down, in a linear equation this relationship is constand but if the line is horizontal though, the distance is not changing despite time passing which means it has come to a stop.

answer; the numbers of valence electrons in the acetic acid molecule (ch3co2h) is 24;