Gymnosperms, or seed-bearing plants, were the only abundant form of plant life during the mesozoic era.

This is false because they weren't the only abundant form of plant life during the Mesozoic Era. There were numerous different types of plants that also used spores or didn't use seeds at all, which points out that this is incorrect. Reptiles fed on them so there was a lot of variety.

~potters6/te801/biology/biounits/respiration.htm