A lactic acid test is a blood test that measures the level of lactic acid made in the body. Most of it is made by muscle tissue and red blood cells.
A biofuel is a fuel that is produced through contemporary biological processes, such as agriculture and anaerobic digestion, rather than a fuel produced by geological processes such as those involved in the formation of fossil fuels, such as coal and petroleum, from prehistoric biological matter.
Biofuel is a term for fuel from plant sources. There are actually lots of different biofuels, many of which are very similar. Biofuels are just fuels which are grown using plant sources (sometimes called biomass) such as hemp, soya, oil seed rape, sugar and palm oil.