Which of the Following Is the Best Answer to the Question

question 95

Multiple Choice

Which of the following is the best answer to the question, "Why does the Sun shine?"

• A)As the Sun was forming, gravitational contraction increased the Sun's temperature until the core became hot enough for nuclear fusion, which ever since has generated the heat that makes the Sun shine.
• B)The Sun initially began generating energy through nuclear fusion as it formed, but today it generates energy primarily through the sunspot cycle.
• C)As the Sun was forming, nuclear fusion reactions in the shrinking clouds of gas slowly became stronger and stronger, until the Sun reached its current luminosity.
• D)The Sun initially began making energy through chemical reactions. These heated the interior enough to allow gravitational contraction and nuclear fusion to occur.

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Definitions:

Lithium

A soft, silver-white metal, the lightest metal and the lightest solid element, used in batteries and certain medicines.

Transition Metals

Elements found in the d-block of the periodic table that have the capability to form positive ions with incomplete d-orbitals.

Metalloids

Elements with properties that are intermediate between those of metals and solid nonmetals.

Atomic Symbols

Abbreviations assigned to elements based on their names, used for representing elements in chemical formulas and equations.