These are bounded opportunities, not learner attainment. Partial and blocked source requirements remain so.

• partial: Know that oceanographers and marine biologists study the ocean using submarines, remotely operated vehicles (ROVs), satellites, and diving, and that much of the ocean remains unexplored — we know more about the Moon's surface than the deep ocean floor

  Bounded objective: Match ocean research tools to questions and constraints. No fragile percentage repeated; NOAA verifies much remains unobserved. Moon-comparison rhetoric is not operationally defined and is not taught as fact.

• partial: Name at least two tools scientists use to explore the ocean: submarines, ROVs, satellites

  ROV/submersible/satellite function choices supplied.

• partial: State that most of the deep ocean remains unexplored

  Much remains unexplored discussed without volatile percentages.

• partial: Explain why ocean exploration is difficult: darkness, pressure, vastness

  Darkness/pressure/area constraints linked to suitable tools.

• partial: Can {{name}} explain how scientists explore the deep ocean using robots and submarines, and why we've still only explored a small fraction of the ocean floor — less than we know about the Moon?

  Try offers supported-explanation for the bounded objective; it does not establish every part of the source assessment. No fragile percentage repeated; NOAA verifies much remains unobserved. Moon-comparison rhetoric is not operationally defined and is not taught as fact.

• No fragile percentage repeated; NOAA verifies much remains unobserved. Moon-comparison rhetoric is not operationally defined and is not taught as fact.