Chemistry Tutorial

Problem 3: Elemental compositions

The elemental composition of the universe, Earth's crust, and the human body differ sharply. What factors might contribute to these differences?

A.	Life evolved in the sea where only a limited number of elements were available.
B.	The elemental composition of the earth is quite different today compared to several billion years ago when life began.
C.	In addition to being available, elements must also be suitable or have properties that are compatible with living processes.
D.	Life probably evolved away from Earth, on a planet where the basic elements that were available were different.