Part $3(0\mathrm{.}2$ point$)$

For this part, make sure both the first and second boxes after both $"$a $($nucl$)"$ and $"$b $($nucl$)"$ are selected. Many green x$\text{'}$s should appear in your $3$D visualization window. Then, go to upper righthand corner of the visualization window of the molecular viewer, where there are three horizontal white lines in a gray box, and left mouse$-$click on this box. You can select many options from this "menu." Try the following:

Change the display of your B$-$DNA so that it is a ribbon display instead of its default space$-$filling display.

$1.)$ On the dropdown menu, scroll down to "display" and hover over the button that looks like two red and blue balls fused together. $"$CPK$"$ will appear if you hover over this button for a moment. This is the "space$-$filling" display that is default on your B$-$DNA structure. Click on the left button of your mouse while hovering over this button. This will de$-$select the CPK display, so your $3$D visualization screen should now be completely empty.

$2.)$ Next, hover over the button that looks like a corkscrew, or a ribbon. "Toggle ribbon for selection" should appear when you hover here. Click on the left button of your mouse while hovering over this button, and then the "ribbon" display of your B$-$DNA should appear. This display makes it easier for you to see certain details in your DNA structure.

$3.)$ View the nucleic acid sequence $($in $1-$letter code for nucleotides$)$ of your protein by selecting "View" and "Sequence View" on this menu. What is the identity of the first nucleotide listed in the sequence view $($the sequence of nucleotides appears in the bottom of the $3$D visualization screen$)?$ Remember: $C$ stands for cytosine, $G$ stands for guanine, $T$ stands for thymine, A stands for adenine, and $U$