Primary energy consumption refers to the total energy demand. Which one of the following observations from the accompanying figure is true? Global primary energy consumption by source (Our World in Data) a. Solar was the most energy-demanding ren

To evaluate the statements based on the unspecified figure on global primary energy consumption by source, we can analyze each statement considering historical trends and general knowledge of energy consumption: a. **Solar was the most energy-demanding renewable source in 1970.** - This statement is likely false, as solar energy consumption was negligible in 1970 compared to other renewable sources like hydropower. b. **The difference in the primary energy consumption of oil in 1965 and 1995 is approximately 15,000 TWh.** - Without specific figure data, this statement is hard to confirm, but oil consumption significantly increased during that period, making 15,000 TWh a reasonable estimate for a significant increase. c. **Natural gas accounted for the greatest primary energy consumption in 2010.** - This could be true, as natural gas consumption increased significantly by 2010, but whether it surpassed oil and coal depends on the detailed data from the figure. d. **The global primary energy consumption of coal in 2009 was approximately 40,000 TWh.** - This figure may or may not be accurate without the specific data, but it is known that coal consumption was substantial around that time; thus, needing verification from the figure. e. **Hydropower was the least energy-demanding renewable source in 1990.** - This statement is likely true, as hydropower was the leading renewable energy source in many regions well before 1990. Given these analyses, the most prudent option without the specific figure being examined is **e. Hydropower was the least energy-demanding renewable source in 1990**, as hydropower has typically been a significant contributor to renewable energy production historically. However, based on your specific needs or focus, options b or c could also be considered depending on the exact figure details.