Liverworts and mosses were some of the earliest land-based plants. which statement correctly explains why these species are still restricted to growing in moist environments? a. they can't absorb water through their roots and must do it through their leaves. b. their gametes must swim in order to interact and for fertilization to occur. c. they don't have cell walls to retain moisture in their cells and dry out otherwise. d. their seeds must absorb water in order to germinate.