Answer:
Step-by-step explanation:
The best way to do this would be to use the following line of code
clear: left;
This would make sure that there are no floating elements (li's in this scenario) on the left side of each element. Which in this navigation list would be each individual element, causing it to move each element underneath the previous element. Therefore the entire CSS code would be
.horizontal li {
display: block;
width: 12.5%;
float: left;
clear: left;
}
An example can be seen in the attached picture below.