Questions: 15 Multiple Choice 1 point How did microbial life on land contribute to the evolution of land plants? By increasing the formation of soil By producing oxygen through photosynthesis By forming symbiotic relationships with marine life By preventing soil erosion

The answer is the first one: By increasing the formation of soil.

Explanation for each option:

1. By increasing the formation of soil: This is correct. Microbial life, such as bacteria and fungi, played a crucial role in the formation of soil by breaking down rocks and organic matter. This process created a suitable environment for land plants to grow and evolve.

2. By producing oxygen through photosynthesis: While photosynthetic microbes like cyanobacteria contributed to oxygen production, this process primarily occurred in aquatic environments before the evolution of land plants. Therefore, this option is not directly related to the evolution of land plants on land.

3. By forming symbiotic relationships with marine life: This option is incorrect in the context of land plants. Symbiotic relationships with marine life do not directly contribute to the evolution of land plants.

4. By preventing soil erosion: While plants and their root systems help prevent soil erosion, this is a function of established plant life rather than a contribution of microbial life to the initial evolution of land plants.

In summary, microbial life contributed to the evolution of land plants primarily by increasing the formation of soil, creating a hospitable environment for plants to colonize land.