1. Cassiopeia A supernova remnant is very colorful. The various colors of gases is caused by their difference in chemical composition. Bright green filaments are rich in which element? Calcium and iron 2. Red and purple filaments are likely Sulphur caused by which element? Hydrogen and nitrogen 3. Blue areas are likely to be rich in which elements? Oxygen 4. Supernova is important in the cycle of stellar evolution in that some important elements are produced only through such process. These elements are?