Complex sentence: Simulations suggest that planets and satellites of less than one Earth mass could have liquid oceans driven by hydrothermal activity, radiogenic heating, or tidal flexing, with the possibility for sustaining simple biological activity over geological timescales.
Split into simpler sentences: Simulations suggest that planets and satellites of less than one Earth mass could have liquid oceans driven by hydrothermal activity, radiogenic heating, or tidal flexing. Liquid water offers the possibility for sustaining simple biological activity over geological timescales.