COMPLETE ME (21-30) Direction: Write the letter that corresponds to the word that best suited the paragraph Write in BIG LETTER the letter of the correct answer in the space provided. Note: Not following instructions may invalidate your answers. A supernova B. Sun C. burning D. nuclear fusion E. Fred Hoyle F Big Bang G. planetary nebula H. chemical elements I. lithium J. red giant star
Stellar Nucleosynthesis is the creation of ________ by __________ reactions within stars. It has occurred since the original creation of hydrogen, helium, and ___________ during the __________ As a predictive theory, it yields accurate estimates of the observed abundances of the elements. It explains why the observed abundances of elements change over time and why some elements and their isotopes are much abundant than others The theory was initially proposed by _________ Stars evolve because of changes in their composition (the abundance of their constituent elements) over their lifespans, first by ________ hydrogen (main sequence star), then helium _______, and progressively burning higher elements. However, this does not by itself significantly alter the abundances of elements in the universe as the elements are contained within the star. Later in its life, a low-mass star will slowly eject its atmosphere via stellar wind forming a _________ while a higher-mass star will eject mass via a sudden catastrophic event called a _________ A second stimulus to understanding the process of stellar nucleosynthesis occurred during the 20th century, when it was realized that the energy released from nuclear fusion reactions accounted for the longevity of the ______________ as a source of heat and light.