This visualization combines a scatter plot with a line chart, showing depth and temperature data from a borehole dataset over time. Users can select which variable to display on the y-axis (Depth or Temp) through dropdown menus built with a custom `dropdownMenu` function. The chart is rendered using D3 v5 with SVG elements, featuring animated circles that transition and expand into place, along with a line path connecting data points. Axes, labels, and gridlines are generated using `d3.axisLeft` and `d3.axisBottom`, with dates formatted via `d3.timeParse` and `d3.timeFormat`.