In 1969, scientists shaved off pieces of the Murchison meteorite and found both D- and L-isomers of ten amino acids.Only L-isomers of amino acids are made by living organisms on Earth.This indicates that
A) Earth's amino acids could not have had an extraterrestrial origin.
B) the meteorite's amino acids as a whole could not have resulted from contamination by Earth organisms.
C) basic chemical building blocks of life have only formed on Earth.
D) life must have originated somewhere other than Earth.
E) life arose in many places besides Earth.

Question

Quizplus · Accepted Answer

The presence of both D- and L-isomers of amino acids in the Murchison meteorite, including the L-isomers only produced by living organisms on Earth, suggests that the meteorite's amino acids did not come from contamination by Earth organisms. Therefore, option B is the best choice. The presence of extraterrestrial amino acids indicates that basic chemical building blocks of life can form elsewhere in the universe, and that life may have originated in many places besides Earth, making options C, D, and E less likely. Option A is also less likely because the extraterrestrial origin of amino acids is supported by the evidence.

In 1969, Scientists Shaved Off Pieces of the Murchison Meteorite