Question

A _____ chart provides a simple way to show trends and variations in a range of data within a single cell

Answer 1

Most reasonable answer is a line chart.
 
With line charts you can spot trends and variations in a certain range of data through different times or just different values of the variable that we plot on the x-axis. In general, line charts are often used in research that wants to depict time trends or how a certain variable progresses through different levels of the variable on the x-axis.