Question

Read this excerpt from a science textbook and answer the question.

The Sun is the star at the center of our solar system. It is truly massive. Our Sun is so large that it contains over 90% of the
matter in the entire solar system. That means that nine out of ten atoms belong to the Sun!
Our star is able to produce heat and light because of a process known as fusion. The Sun does not have a crust like solid planets
do. Instead, the visible edge of the Sun is the edge of its photosphere. Inside the Sun, temperatures can reach over 13,000,000
Kelvin!
The words "matter," "photosphere," "fusion," and "Kelvin" are bolded in the paragraph above because
bold words are defined in the book's glossary.
bold words are always from foreign languages.
words that are hard to understand are bold.
bonus words are always bold in a textbook.
OA.
OB.
OC.
OD.

Answer 1

The bold words in the textbook excerpt are bolded because they are defined in the book's glossary, and they represent important concepts in the study of the Sun and stars.

Step-by-step explanation:

The words "matter," "photosphere," "fusion," and "Kelvin" are bolded in the paragraph because bold words are defined in the book's glossary. These terms are likely technical vocabulary related to the study of the Sun and stars, which would be explained in the glossary to help readers understand their meanings in the context of the topic. For instance, 'matter' refers to the substance that makes up the Sun and all objects in the universe, the 'photosphere' is the visible surface layer of the Sun, 'fusion' is the process that powers stars, including the Sun, by combining lighter elements into heavier ones, and 'Kelvin' is a unit of measurement for temperature used in the physical sciences.