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black hole
Oort cloud
star types (supergiant, red dwarf, white dwarf)
supernovae
planetary nebulae
Andromeda galaxy
quasar
Use the library and other resource materials to research and understand your topic. Remember that nasa. gov is a web site that has reliable information as well that you may use for your research. Now write a 300-word report on what you have learned.

i thinking chemical change

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.