if the earth had no atmosphere no greenhouse gases and no heat trapped in its system what approximate earths sunface bea 18℃b -18℃c 80℃d -8℃

Without an atmosphere, greenhouse gases, and trapped heat, the Earth's surface temperature would primarily be determined by the balance between the incoming solar radiation and the outgoing radiation. The average temperature of the Earth's surface without these factors is estimated to be around -18℃ (b).