Which of the following was a major effect of the first land plants on life on Earth?

• A. Reduction in terrestrial biodiversity
• B. Increased atmospheric oxygen through photosynthesis
• C. Decreased soil formation and nutrient cycling
• D. Elimination of aquatic habitats

Answer: (B)

Verified step by step guidance

1. Understand the role of the first land plants in Earth's history. Land plants were among the first organisms to colonize terrestrial environments, and their presence had significant ecological and atmospheric impacts.
2. Recall the process of photosynthesis. Land plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. This process contributes to the increase of atmospheric oxygen levels.
3. Consider the ecological effects of land plants. By stabilizing soil and promoting nutrient cycling, land plants supported the development of terrestrial ecosystems and increased biodiversity rather than reducing it.
4. Evaluate the options provided in the question. The correct answer should align with the major ecological and atmospheric contributions of land plants, such as increased oxygen levels and enhanced soil formation.
5. Select the correct answer: 'Increased atmospheric oxygen through photosynthesis,' as this reflects the significant impact of the first land plants on Earth's atmosphere and ecosystems.