Update contribution.html

wiki/pages/contribution.html

@@ -214,7 +214,7 @@ Reference: Phage t7 promoters for boosting in vitro transcription. Thomas Conrad
         <figure>
           <img src="https://static.igem.wiki/teams/4697/wiki/graph2.png" class="content-img img-fluid py-6" style="margin-top: 20px;width: 800px;margin-left: 5%;">
           <figcaption>
-            <p><b><u>Graph 2  :</u></b> 
+            <p><b><u>Graph 2  :</u></b> Fluorescence detection for old RNA (ng/uL).
           </figcaption>
         </figure>