The following questions are based on four passages in English to test the comprehension of English language. Read each passage and answer the questions.
As seen from space, it is a rotating blue ball streaked with varying cloud patches, reddish-brown deserts and brilliant white polar caps. The energy for heating the Earth comes almost exclusively from sunlight, the energy conducted up from the hot interior of the Earth amounting to less than one thousandth of one per cent of that arriving in the form of visible light from the Sun. But not all the sunlight is absorbed by the Earth. Some is reflected back to space by polar ice, cloud, and the rocks and water on the surface of the Earth. The average reflectivity, or albedo, of the Earth, as measured directly from statellites and indirectly from Earthshine reflected off the dark side of the Moon, is about 35 percent. The 65 percent of sunlight that is absorbed by the Earth heats it to a temperature which can readily be calculated. This temperature is about 18ºc, below the freezing point of seawater and some 30ºc colder than the measured average temperature of the Earth.
Which is the main source of Energy to heat the Earth?