Life on Earth Did Not Originate from Mars or Asteroids.

Life on Earth is made of left-handed amino acids (note 1). Life does not use right-handed amino acids. Left-handed-only amino acids are not found in samples collected from asteroid Ryugu (note 2). Left-handed-only amino acids are not found in meteorites, asteroids or Mars. Right-handed amino acids do not evolve into 100% left-handed amino acids. So, life on Earth did not come from Mars or asteroids or meteorites.

Note 1: "Life on Earth is made of left handed amino acids,..." (quoted from the first paragraph in [link to www.vanderbilt.edu (secure)] )
Note 2: see news at [link to mainichi.jp (secure)]