Which
world
is
the
biggest​

If you are asking which county is biggest it's Russia , Asia is the biggest continent

Explanation:

If you are asking what country is the biggest, it's Russia. If you're asking what the biggest planet is, it's Jupiter. And if you're asking the biggest continent, it's Asia.

"the day we found the sharks' teeth" i would say highlight the element of the plot as it sets its boundaries and centers the adventures of them being on a boat and cleaning spit of sand.