How can friction be when riding a bicycle and how can it be harmful

Calculate: select the worksheet tab. this tab you calculate the analyte concentration.  fill in the first set of boxes ("moles h2so4" and "moles naoh") based on the coefficients in the balanced equation. (if there is no coefficient, the value is 1.)  record the appropriate volumes in the "ml naoh" and "ml h2so4" boxes.  record the concentration of the titrant in the m naoh box. click calculate. what is the concentration listed

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?

Chemistry worksheet - i am not sure what they are asking for exactly?