4) empress si-ling chi observed in her garden. a: fossil boneb: silk wormsc: fishd: secretse: mulberry trees (this is the answer)

The answer is: B) silkworms.

“While sitting in her garden she deduced the secret of silk by watching the silkworms. She developed the process to remove the thread from the cocoon and set up silk cultivation farms and the weaving of the new cloth.” (Source: http://4kyws.ua.edu/SI_LING_CHI.html)

Ibelieve its b but u might have to