A fireman turns on a hose
and is knocked backwards.

Biomass can be used to generate electricity. biomass relies heavily on agricultural crops. plants release carbon dioxide and water in combustion. plants use photosynthesis to originally generate the energy that is needed. the chemical energy of these plants all started with what energy source?

Which of the following produces carbon dioxide? a. plants b. animals c. decomposers d. all of the above

The vaccine in a flu shot contains weakened flu viruses. how does a flu shot work with the immune system? a. it destroys lymphocytes. b. it destroys macrophages. c. it activates macrophages. d. it activates lymphocytes.