.

The first c.d. was released after the phonograph. 75 years 200 years 100 years 50 years

1× 10×10×10+2×30×30=[tex]1 \times 10(4) + 2 \times 10(3) = \\ [/tex]

Which does the author mean by " nature had to kindle all the fires, for man by his own effort was unable to produce a spark