Which of the following actions is illegal while driving?

Texting while driving is illegal due to the significant distraction it causes. When drivers engage in texting, their attention is diverted from the road, which increases the risk of accidents. This action hampers their ability to react quickly to changing conditions and diminishes their awareness of surroundings.

In contrast, using a turn signal when changing lanes is a legal and responsible action, as it communicates your intentions to other drivers and helps prevent collisions. Adjusting your seat before starting your journey is also legal and advisable for ensuring comfort and proper control of the vehicle. Stopping at a crosswalk is a required action to yield to pedestrians, contributing to road safety. Thus, texting while driving stands out as the illegal action in this context.