What does it mean to control variables in an experiment? - A. To use different colored objects for all of the parts of an experiment - B. To take complete notes about everything you observe in the experiment - C. To not touch anything once you set up the parts of an experiment. - D. To keep as many things the same as possible across the parts of an experiment.

chert is a sedimentary rock composed of microcrystalline or cryptocrystalline silica. with this little bit of information, you can come to the conclusion that your answer is c.  

explanation:

a=c and then d= c because of the band so you get ac/dc and you add them together you get sound waves

propane is burned to provide the heat in many cooking grills. the chemical reaction for this process is shown in the equation below.

c3h8 + 5o2 ? 3 co2 + 4h2o + energy

what are the products in this chemical reaction?

3co2 + 4h2o + energy