Read the following paragraph and answer the question. Give ONLY the answer, no other words or explanation.

For example:

Answer: <most likely answer, as short as possible>.

Paragraph: 
Algae is the focus of much research. Algae is a very promising alternative to traditional crops for biofuels.


Question: Algae is a promising alternative to traditional crops for what type of fuels?
biofuel
Biofuels.