In this task, we ask you to rewrite a sentence in simple English without changing its general meaning. Essentially, you want to make the sentence easier to read by using simpler words, utilizing more straightforward sentence structures, and omitting non-essential information etc.

As a philosopher , Ernst Haeckel wrote " Die Weltra thsel " ( 1895 1899 ; in English : " The Riddle of the Universe " , 1901 ) , the genesis for the term " world riddle " ( " Weltra tsel " ) ; and " Freedom in Science and Teaching " to support teaching evolution .
As a philosopher , Ernst Haeckel wrote " Die Weltra tsel " ( 1895 1899 , " The Riddle of the Universe " , 1901 ) , and " Freedom in Science and Teaching " to support teaching evolution .

The Vatican Apostolic Library , more commonly known as the Vatican Library or informally as the Vat , is the library of the Holy See , located in Vatican City .
The Vatican Library is the library of the Holy See .

The archaeologists said the bones were from a boy who was roughly between the ages of ten and thirteen years at the time of his death and of a young woman who was roughly between the ages of eighteen and twenty-three years old .
The archaeologists said that the bones were from a boy who was about 10 to 13 , and a young woman who was between 18 and 23 years old .