Detailed Instructions: In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.
See one example below:
Problem: The Inheritance Cycle is a series of fantasy books written by Christopher Paolini.
Solution: The Inheritance Cycle is a tetralogy of young adult high fantasy novels written by American author Christopher Paolini.
Explanation: The output sentence elaborates on the input sentence without changing its general meaning e.g. "tetralogy of young adult high fantasy novels".

Problem: The name is because radioactive material " falls out " of the atmosphere into which it is spread during the explosion .
Solution:
Nuclear fallout , or fallout , is the residual radioactive material propelled into the upper atmosphere following a nuclear blast , so called because it " falls out " of the sky after the explosion and the shock wave have passed .