Cyanobacteria have been engineered to produce isobutanol directly. what advantage does this have over other alternative biofuels?

a. it is an inherently renewable fuel source.
b. multiple processing steps can be avoided.
c. they produce chemical energy through photosynthesis.
d. they make a biofuel alternative to gasoline.

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.

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.