# Units 10–12 Cumulative Benchmark Study Guide

## Structure
- 60 objective questions: 20 each from Units 10, 11, and 12
- Four constructed responses
- Objective mastery: 48/60
- Recommended final mastery: 80/100
- Calculator and blank paper permitted
- Corrections and retakes permitted
- Public benchmark is formative; official mastery remains separately supervised and authenticated

## Unit 10 — Earth Systems & Biogeochemical Cycles
Review Earth-system spheres, reservoirs, fluxes, feedbacks, boundaries and scales; evidence about Earth’s interior; plate motion and hazards; rock, water, carbon, nitrogen and phosphorus cycles; reservoir budgets; Earth’s energy balance; greenhouse effect, forcing, feedback, variability, scenarios and uncertainty; observations, resilience, stewardship, justice and monitoring.

## Unit 11 — Space Systems, Astronomy & Cosmic Evidence
Review apparent sky motion, seasons, lunar phases and eclipses; astronomical units, light-time and light-years; gravity and orbital motion; Solar-System formation; solar structure and fusion; spectra; stellar life cycles; exoplanet transit and radial-velocity evidence; transit depth and radius ratio; redshift and Hubble-law reasoning; galaxies, lookback time, cosmic expansion, CMB and composition evidence; mission ethics and uncertainty.

## Unit 12 — Sustainable Engineering Capstone
Review stakeholders, system boundaries, criteria and constraints; scientific evidence and conflicts of interest; weighted decision matrices; mathematical models, simulations and safe prototypes; repeated trials; life-cycle and circularity impacts; hazards, failure modes, controls and residual risk; sensitivity analysis; optimization; accessibility, equity, privacy, labor, cultural and environmental-justice considerations; reproducible recommendations and monitoring.

## Core calculations
- Reservoir final amount = initial + inputs − outputs
- Absorbed energy = incoming energy × (1 − reflected fraction)
- Transit depth ≈ (planet radius ÷ star radius)²
- Percent change = (final − initial) ÷ initial × 100
- Weighted score = Σ(score × criterion weight)
- Percent error or difference must state the reference quantity used

## Integration bridge
Earth and space science depend heavily on indirect measurements, while engineering converts scientific evidence into monitored, testable decisions. Be ready to distinguish observation from inference, preserve raw data, state uncertainty, define criteria and constraints, and revise a model or design when evidence changes.