Newsela Life and Purpose: A Biologist Reflects on the
Qualities that Define Life
By Ursula Goodenough, Big History Project on 07.31.16
Word Count 1,071
Lovel MAX
light energy into food. The molecules that are made as a consequence of photosynthesis can be
leased to drive self-generation Photo: Big History Project
a to define
What makes something alive ?

b ti isnfornopgnoernfrof

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.