What are the possible reasons for the transition of plants to a terrestrial lifestyle?

The transition of plants to life outside the aquatic environment is associated with periodic drying out and flooding of certain areas of the seabed. The seawater retreating during low tides lingered in the depressions of the bottom, thereby creating independent pools, which either completely dried up, then again filled with water. The pools were inhabited by a variety of unicellular algae. Thus, some species of algae and managed to gradually adapt to living on land. Botanists believe that the first plants to master the land were plants whose direct ancestors were ancient green algae. As a result of evolution, these plants have developed female and male reproductive organs with protected gametes.