What is the difference between haploid and diploid cells? Which process creates diploid cells? Which process creates haploid cells please do this pretty simple because I'm a dummy lol

The ancestors of plants that lived in water had plenty of water for the young. angiosperms are a group of land plants that evolved a reproductive trait for living on land. this trait protect young plants by allowing them to grow only when water is present and the conditions for healthy development are right. what trait most likely young angiosperms in this way?