You didn’t give any options but i’m assuming it’s “oxygen”
Herbivores in the ocean include the marble parrotfish, pin fish, surgeonfish, damselfish, and rabbit fish.
The Mayan and other Mesoamerican cultures used a vigesimal number system based on base 20 (and, to some extent, base 5), probably originally developed from counting on fingers and toes. The numerals consisted of only three symbols: zero, represented as a shell shape; one, a dot; and five, a bar.
