<span>d. tightly packed particles</span>
Melting ice cream is a physical change because it is a phase change, the water in the ice cream gains thermal energy and the inter-molecular forces are overcome and the molecules move further apart forming a liquid. It is not a chemical change because no chemical reactions occurred.
During El Niño, changes in wind and ocean current patterns result in warm waters stretching across the whole Pacific Ocean. This extra heating causes changes in wind patterns, which causes atmosphere to react and change all the way from the ground to the edge of space around Earth.