sentences: a human cell is a kind of cell
docs: human_cell has membrane human_cell is vertebrate_cells. human_cell is animal_cell. human_kidney_cell is human_cell. human_pancreatic_cell is human_cell. human_cells is biological_cells. human_somatic_cell is human_cell. human_cell is cell. human_liver_cell is cell. human_gametes is human_cell.