Answer: 300 slaves
Explanation: Harriet Tubman is perhaps the most well-known of all the Underground Railroad's "conductors." During a ten-year span she made 19 trips into the South and escorted over 300 slaves to freedom.
A power companies increased rates
The answer is b.Multiple processing steps can be avoided.
Traditionally, energy crops are used for ethanol production thanks to yeast cultures. But, cyanobacteria can naturally ferment alcohol, such as isobutanol, without the need of yeast cultures. This way some steps are avoided and the process is faster. Also, cyanobacteria have a fast life cycle, so it can be produced great amounts of isobutanol for a short period of time.
