Discussion topic
chemical energy sources are often portable and provide large amounts of energy. fossil fuels are one kind of chemical energy source. most of the energy we use in the united states is generated by the combustion of fossil fuels. however, fossil fuel combustion adds greenhouse gases to the atmosphere, mostly co2. one measure of the total amount of greenhouse gases that are emitted into the atmosphere each year is called a carbon footprint. read this article to compare the carbon footprint of an average person in the united states to an average person around the
world. knowing that greenhouse gases are
contributing to climate change, how can we
reduce our carbon footprint, particularly in the
united states? could hydrogen fuel replace
fossil fuels in the future? why or why not? should the size of a person's carbon footprint be limited by law? why or why not?

Astudent from one of the research labs is having trouble preparing a slide for examination and photographing. the bacterial slide that he has brought to you was prepared using a commercially purchased stain. he has asked for your in determining what he is doing wrong so that he can change the lab protocols and continue on with his project. after examining the slide under oil immersion, you determine that no bacteria are present even though the student is able to show you the culture he used to make that slide that has visible growth in the liquid medium. which of the following statements does not explain the fact that there are no bacteria present on the student’s slide? by not allowing a glass slide to completely air dry before heat fixation, the flame will cause the surrounding water to boil and this will damage the bacterial cell. overheating during the fixation step boiled the water within the bacterial cells and resulted in the cells bursting. insufficient heating of the slide did not drive out the thin layer of water and this resulted in minimal bonding between the bacteria and the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide.