<span>The correct answer is letter "d. It's used to make paper products." Cellulose is considered to be a major material used in creating a vast amount of paper products, such as papers, paperboards, and even cardboards. Cellulose can also be used as an important fiber as an important material in textiles.</span>
The correct pairing of the volcano to its formation would be the composite volcano wherein it usually yields large and violent eruptions. In addition to that, composite volcanoes or also known as the stratovolcano is usually made of materials containing increasing layers of hardened lava.
1) Carbon-13:
Proton-6 Neutron-7 Electron-6
2)Atomic mass of element X:
(55*10+56*20+57*70)/100=56.6
STP condition mean we have P=1 atm. T=273K. R=ideal gas constant, but make sure you use the one that has the same units of pressure, temperature that you are using. In this case R=0.0821 L*atm K^-1mol^1. You are provided with n=2.1 moles.
V=nRTP
Input your values and solve.