Rearrange the following in increasing order of evolution?
Gnetales, Ferns, Zosterophyllum, Ginkgo

Explanation

To arrange the given groups in increasing order of evolution, we need to understand the evolutionary timeline of each group:

1. **Zosterophyllum**: This is an early vascular plant that existed during the Devonian period. It is considered one of the earliest land plants and represents a primitive stage in plant evolution.

2. **Ferns**: Ferns are more advanced than Zosterophyllum and appeared later in the evolutionary timeline. They are part of the Pteridophytes group and have a more complex structure compared to early vascular plants.

3. **Ginkgo**: Ginkgo biloba is a unique species of tree that is part of the Ginkgoales. It is more evolved than ferns and represents a group of seed plants that appeared later in the evolution of plants.

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