Although the atrocities against african americans were well known, why was so little done to prevent them?

Why does the blending of many different diciplines present both challenges and opportunities to enviromental scientist?

1. the community center is putting on a play. there are several things the crew has to create for the scenery. (a) they spent $6.17 on each of 4 poster boards. how much did they spend on poster boards in total? show your work. (b) they spent $200.20 total on new lighting. each of the four lights cost the same amount. how much did they pay per light? show your work. (c) if the total budget was $300, how much more can they spend? show your work.

50 ppm (50 mg/kg) is equal to 0.005%. how many ppm is equal to 5%?