Go to www.online history degrees.com and you will find it
Sand can be used for glass.
They should interview other people who fought in that same war ( which would be back up witness for these two different accounts). So whoever has the most back up witnesses must be telling the truth ( also make sure the other people you interview don't know they are back up witness).
The answer is D. 12 cm, because in order to find the area of a parallelogram you need the formula A = (b)(h), which is base times height. So 20cm x 12cm equals 240cm^2 :)