Is this a run-on sentence
Inside its tissues, the spotted jelly—a marine invertebrate native to the South Pacific—grows symbiotic algae that produces food for the jelly and gives it a greenish-brown hue.

Yes

Explanation:

You have multiple dashes and could easily delete them and make this sentence multiple sentences.

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(the answer is d)

hope this !

this story explains the proverb “small acts of kindness will be rewarded greatly” and how anyone regardless of their size and appearance, can make a major impact in certain situations. this tale can teach your child to appreciate others and create a tendency in their minds.