You are given a sentence and your task is to generate another sentence that supports the given input.

[EX Q]: The light travel time for the most distant visible galaxies is several billion years, comparable to the age of the universe, so by studying distant galaxies we are also looking back in time.
[EX A]: Due to the time it takes for light to reach us, galaxies at the edge of the universe are distant in terms of space and time.

[EX Q]: As alternating current moves back and forth in a wire, magnetic fields are created around the wire.
[EX A]: Alternative current is produced when a magnet or coil moves back and forth repeatedly.

[EX Q]: Features of pollen grains used in identification are size, shape, thickness of the exine (outer wall) and intine (inner wall) of the pollen grain.
[EX A]:
Each pollen grain has two coverings: the exine (thicker, outer layer) and the intine.