Pacific Ocean
Sharing a common border throughout its northern extent with the United States, Mexico is bounded to the west and south by the Pacific Ocean, to the east by the Gulf of Mexico and the Caribbean Sea, and to the southeast by Guatemala and Belize.
Hope it helps you
"The Silurian is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago, to the beginning of the Devonian Period, 419.2 Mya.<span> <span>Wikipedia."
https://www.google.com/search?q=He+Silurian+period+occurred&rlz=1C1RUCY_enUS760US760&oq=He+Silurian+...
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D Easy I think because all the others are posotive
