What is the concentration in parts per million of D. D. T. A non biodegradable pesticide in two mg in one kg needle fish tissue? All right, so we want parts per million. So that's going to equal the grams of our salute, divided by grants of solution Times 10 to the six. We have an issue, though these units are not. Ingram's ones and milligrams once in kilograms convert them both to Graham's first. So we have two mg. I remember one mg when Millie is 10 to the negative three. So that's 2.0 times 10 to the -3 gramps And then remember, one kg is equivalent to 1000 g. So we take that and plug it in. So we have 2.0 times 10 to the negative three g divided by 1000 g Times 10 to the six. When we do that, we get back to 0.0 ppm, so that will be our parts per million of DDT. For this particular example, question