Conditionals are lines of code that can preform different fuctions based on different information and decisions.
if (time < 10) { greeting = "Good morning"; } else if (time < 20) { greeting = "Good day"; } else { greeting = "Good evening"; }
Based on the line of code at time before 10 will give good morning. The time before 20 will be good day. All other values will give good evening.