HS-ESS2-6

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Develop a quantitative model to describe the cycling of carbon among the hydrosphere, atmosphere, geosphere, and biosphere.

Clarification statement: Emphasis is on modeling biogeochemical cycles that include the cycling of carbon through the ocean, atmosphere, soil, and biosphere (including humans), providing the foundation for living organisms.

Note: this is a performance expectation for both HS Earth & Space Science and HS Biology. For biology, the focus is on "the biochemistry aspects of carbon cycling". For Earth & Space Science, the focus is on "physical and chemical aspects of the geochemical cycling of carbon" (as per the NYSED high school course maps).

Regents Exam Questions

Released New York State Regents exam questions that assess HS-ESS2-6 are listed here by exam and question cluster. Each link opens the question with its answer key.

Biology

Exam	Cluster	Question
August 2026 Biology Regents	The Permafrost Problem	Question 46
June 2026 Biology Regents	Fossil Fuels: Out of Sight, but Not Out of Mind	Question 26
January 2026 Biology Regents	Keystone Species Rule	Question 11
	Purple Insect Eater	Question 38
August 2025 Biology Regents	Trees Have Organ Systems	Question 4
	Carbon Cycle Supports Life on Earth	Question 22
	Carbon Cycle Supports Life on Earth	Question 23
June 2025 Biology Regents	Carbon! Where Does It Come From? Where Does It Go?	Question 5
	Does It Matter?	Question 37

Earth & Space Science

Exam	Cluster	Question
August 2026 Earth and Space Sciences Regents	Carbon Emissions in Industry	Question 24
June 2026 Earth and Space Sciences Regents	The Slow Carbon Cycle	Question 9
	Lake Nyos	Question 34
January 2026 Earth and Space Sciences Regents	The Carboniferous Period	Question 50
June 2025 Earth and Space Sciences Regents	The Carbon Cycle	Question 12
Earth and Space Sciences sample clusters (Fall 2024)	Theia and the Moon	Question 6

Vocabulary

Terms that come from this standard or from the released exam questions that assess it, listed by subject. Biology terms are from the Biology Glossary; Earth & Space Science terms are from the Earth & Space Science Glossary.

Biology

From this standard

• atmosphere
• biogeochemical cycles
• biosphere
• carbon
• carbon cycle
• carbon dioxide concentration
• climate
• closed system
• cycling of carbon
• geosphere
• human activity
• hydrosphere
• matter
• ocean
• oxygen
• quantitative model
• soil

From released exam questions

• carbon sequestration – Aug 2025
• carbon sink – Aug 2025
• carbon storage – Aug 2025
• combustion – June 2026
• cycling of matter – June 2025
• Earth’s spheres – Jan 2026
• ecosystem – Aug 2026, Jan 2026
• hydrogen – June 2025
• keystone species – Jan 2026
• land use – June 2026
• migration – Aug 2025
• ocean acidification – June 2025
• permafrost – Aug 2026
• pH – June 2025
• photosynthesis – Jan 2026, Aug 2025
• population – Aug 2025
• resources – June 2025
• respiration – Aug 2025
• species – Aug 2025
• waste – Aug 2025

Earth & Space Science

From this standard

• atmosphere
• biogeochemical cycles
• biosphere
• carbon
• carbon cycle
• carbon dioxide
• carbon dioxide concentrations
• cycling of carbon
• Earth
• geosphere
• human activity
• hydrosphere
• living organisms
• model
• ocean
• oxygen
• quantitative model
• soil

From released exam questions

• air-sea gas exchange – June 2025
• biomass – Jan 2026, June 2025
• coal – Jan 2026
• decomposition – June 2025
• dissolution – June 2026
• emissions – June 2025
• erosion – June 2026
• fast carbon cycle – June 2025
• fossil fuels – Aug 2026
• geologic processes – June 2026
• iron – June 2025
• magma – June 2026
• mantle – June 2026
• minerals – June 2026
• ocean floor – June 2026
• respiration – June 2025
• river valley – Jan 2026
• sediment – Aug 2026, June 2025
• sedimentary rock – June 2026
• sedimentation – June 2026
• slow carbon cycle – June 2026
• soil carbon – June 2025
• subduction – June 2026
• volcanic activity – June 2026
• volcanism – June 2026
• weathering – June 2026

Performance Level Descriptions

Every Regents exam question on HS-ESS2-6 is written to match one of the performance level descriptions (PLDs) below.

Level 1: Use a quantitative/qualitative model that shows the cycling of carbon between two Earth spheres to identify the relative concentrations of carbon present in each sphere. Aug 2026 ESS · Q24

Level 2: Use a quantitative/qualitative model to identify the cycling of carbon between two Earth spheres (hydrosphere, atmosphere, geosphere, and biosphere). Jan 2026 Bio · Q11 Jan 2026 Bio · Q38 Aug 2025 Bio · Q23 June 2026 ESS · Q34 Jan 2026 ESS · Q50 June 2025 ESS · Q6 June 2025 ESS · Q12

Level 3: Use/complete a quantitative model to describe the cycling of carbon between two Earth spheres (hydrosphere, atmosphere, geosphere, and biosphere). Aug 2026 Bio · Q46 June 2026 Bio · Q26 Aug 2025 Bio · Q22 Aug 2025 Bio · Q4 June 2025 Bio · Q5 June 2025 Bio · Q37 June 2026 ESS · Q9

Level 4: Develop a quantitative model to describe the cycling of carbon among the hydrosphere, atmosphere, geosphere, and biosphere.

Level 5: Develop and analyze data from a quantitative model of the carbon cycle to predict how a change in carbon levels in one system will affect other Earth systems.

Notice: PLD levels!

Resources

Examples and discussion of resources for the learning, teaching, and assessment of HS-ESS2-6.

This section could be expanded upon. You can help out by adding to this section.

NGSS Dimensions

Performance expectation HS-ESS2-6 was developed using the following elements from the NRC document A Framework for K-12 Science Education:

Science and Engineering Practices

• Developing and Using Models
  • Develop a model based on evidence to illustrate the relationships between systems or between components of a system.

Disciplinary Core Ideas

• ESS2.D: Weather and Climate
  • Gradual atmospheric changes were due to plants and other organisms that captured carbon dioxide and released oxygen.
  • Changes in the atmosphere due to human activity have increased carbon dioxide concentrations and thus affect climate.

Crosscutting Concepts

• Energy and Matter
  • The total amount of energy and matter in closed systems is conserved.

Page contributors: Conrad Richman, Caroline Leonard

Earth and Space Science and Biology | HS. Earth's Systems