There’s another paper to this, please help i don’t pay attention in class

What does the process of natural selection involve

Fill in the coefficients that will balance the following reaction: a0cr2(so4)3 + a1agno3

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ