Analysis of comet dust collected and returned to Earth by the Stardust mission has shown that
A) simple life exists in comets
B) organic molecules can form in space and survive the passage through the Earth's atmosphere
C) organic molecules are completely absent in comet dust so impacts could not have made a significant contribution the organic material present on the early Earth
D) impacts must have been the only source of organic material present on the early Earth

Question

Quizplus · Accepted Answer

Analysis of comet dust collected by the Stardust mission has shown that organic molecules can form in space and survive the passage through the Earth's atmosphere. This suggests that comets may have contributed to the organic material present on the early Earth, adding to the various hypotheses of the origin of life on Earth. However, no evidence of simple life existing in comets has been found. Organic molecules are also present in other interstellar and planetary environments. Therefore, the absence of such molecules in comet dust cannot be concluded.

Analysis of Comet Dust Collected and Returned to Earth by the Stardust