Exercise 3 solution (model answer; yours will use a different statistic)

Statistic: "We have explored only five per cent of the ocean."

1. It claims that almost all of the ocean has never been seen or surveyed by people.
2. To support it, someone would have to define "explored" (visited? mapped by sonar? sampled?) and measure the share of area or volume that meets the definition. The ocean is three-dimensional, so area and volume give different answers.
3. It is usually traced back to loose wording about seafloor mapping. A better-defined figure is the share of seafloor mapped to modern standards, which the Seabed 2030 project reports regularly, so the useful habit is to look for the original source and its definition.