Petroleum ( like Oil, diesel, gases), electrical power and Nuclear power replaced wood and steam, due to development in our technology.
Hope this helps!
In ancient history we can only study their cultures. This is because they didn't always have written records (or the records they did leave has been destroyed or damaged) hence no way to transmit their information. We have to guess on their everyday lives based on statues and art forms they left behind.
There are 5 significant figures in the number 84062.
There are 5 digits at all, and none of them are leading zeros (they are always insignificant). Also there are no trailing zeros (they are sometimes considered insignificant).
And because we know nothing about the precision of the original data, if this number is obtained from some calculations, we have to assume all digits significant.
Zero inside the number is significant, too, because it gives important...
I would try D. Fourth option as an answer.
Look into OYEZ.org for possible answers.