sentences: the freezing point of water / melting point of water is 32f / 0c / 273k & 0 c is lower than 1538 c & the melting point of iron is 2800f / 1538c / 1811k ->  the melting point of water is lower than the melting point of iron  -2188 c is lower than 0 c & the freezing point of water / melting point of water is 32f / 0c / 273k & the melting point of oxygen is -3618f / -2188c / 544k ->  the melting point of oxygen is lower than the melting point of water  the melting point of water is lower than the melting point of iron & the melting point of oxygen is lower than the melting point of water -> the melting point of oxygen is lower than water and the melting point of water is lower than iron