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9.2 Earth and atmospheric science

9.2 Earth and atmospheric science

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Question 50

Algae first evolved in the oceans around 2.7 billion years ago. Following this, the concentration of oxygen in the Earth's atmosphere began to rise.

Explain how the evolution of algae and early plants caused this increase in oxygen.

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Markscheme

9.2 Earth and atmospheric science Questions

  1. GCSE
  2. /Chemistry
  3. /9.2 Earth and atmospheric science

97 exam-style questions on Edexcel GCSE Chemistry 9.2 Earth and atmospheric science, covering 9.2.1 The Earth's early atmosphere, 9.2.2 How the atmosphere evolved, 9.2.3 Chemical test for oxygen, and 9.2.4 The greenhouse effect and climate change. Each one has a worked solution and a mark scheme showing where the marks go.

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