The graph shows the mass of a radioactive substance as a function of time

enter the initial mass of the substance box.

__g

To know the initial amount of the radioactive substance, you should read the graph in the y - axis when the x = 0, because at x = 0 this means the intial point of the graph or the initial amount of the substance. so at x  = 0 the y = 45 so the initial amount is 45 g

The Correct answer to your

question is 45 g. if you are wondering how I know I just did the 6.05 test in Algebra I (K12). I hope I helped you Today!