Question

which of the following is a drawback to using biofuels, such as ethanol, as a fuel source?
a ethanol - blended gasoline has higher carbon emissions than petroleum alone.
b the global demand for biofuels is continually decreasing.
c there is high energy investment in producing and processing the crops needed for ethanol production.
d ethanol - blended gasoline increases the likelihood of freezing gas lines in winter months.

Explanation:

• Option A: Ethanol - blended gasoline generally has lower carbon emissions than petroleum alone because ethanol is a renewable fuel. So, this option is incorrect.
• Option B: The global demand for biofuels is actually increasing as countries look for alternatives to fossil fuels. So, this option is incorrect.
• Option C: Producing and processing crops for ethanol (like corn for ethanol in some cases) requires significant energy input. For example, energy is used in farming (tilling, fertilizing, harvesting) and in the distillation process to convert the crop material into ethanol. This is a valid drawback.
• Option D: Ethanol - blended gasoline has a lower freezing point than pure gasoline. So, it does not increase the likelihood of freezing gas lines in winter. This option is incorrect.

Answer:

C. There is high energy investment in producing and processing the crops needed for ethanol production.