# A science journalist is writing an article about the origins of the chemical elements found in living organisms. The journalist states: 'The atoms in your body were forged in stars billions of years ago.' Explain how nuclear fusion in stars produces heavier elements from hydrogen, and describe how these elements eventually become part of living organisms on Earth.

> OCR A-Level Chemistry B: Salters (H433) — EL Elements of life · Explain · 5 marks

> All living organisms are made mainly from a small number of non-metal elements. These elements were not present at the very beginning of the universe but were formed later through processes inside stars.

## Mark scheme (5 marks)

1. Hydrogen was the first element formed / the universe began with hydrogen (and helium)
2. Nuclear fusion joins smaller nuclei together to form larger/heavier nuclei
3. Elements up to iron are formed by nuclear fusion inside stars
4. When stars explode (supernova) / die, the elements are released / dispersed into space
5. These elements became part of the Earth / were incorporated into molecules that make up living organisms

## Key terms

- [nuclear fusion](https://www.gradenine.co.uk/glossary/nuclear-fusion)
- [element](https://www.gradenine.co.uk/glossary/element)
- [hydrogen](https://www.gradenine.co.uk/glossary/hydrogen)

## Related

- [Revision notes for OCR A-Level Chemistry B: Salters (H433)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/a-science-journalist-is-writing-an-6610dc0b) · Published by Druglandscape Ltd.