How many liters of water vapor, measured at STP, would be produced by the combination of 45.0 L of oxygen (O2)?

answer is d because it is trust me

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

i think that the answer is c

qualitative observation deals with data that can be observed with our senses: sight, smell, touch, taste, and hearing. they do not involve measurements or numbers. for instance, colors, shapes, and textures of objects are all qualitative observations.