What are all examples of biotic factors running log, stream water, dead leaves, bacteria, soil

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

1) which of the following is the best example of a physical change? a) sugar dissolving in tea b) firefly glowing 2) in the combustion of ethane, what is/are the reactants? c2h6 + o2 ==> co2 + h2o a) c2h6 and o2 b) co2 and c2h6

Which property of water causes water drops to bead on a freshly waxed car?