A line graph captioned 'Human Population Growth, 10,000 B.C. to 2000 A.D' is plotted between 'Year' in x-axis ranging from 10000 B.C to 2000 A.D. and 'Population in millions' in y-axis ranging from 0 to 7 with an increment of 1. The graph is flat initially and then grows exponentially. There are four sections marked:

1. Agriculture begins.
2. Plowing and irrigation.
3. Bubonic plague.
4. Industrial revolution begins.