Rachel M. answered • 02/07/20
Dedicated + Patient Educator for Live or Online Tutoring
Thank you for the link to the practice test, because the passage is needed to complete this.
Also, it is good to note that 3 options will not be used, while there will be 3 against and 4 in support of this concept.
In order to better understand which options would support the idea of "panspermia" and which would be against it, it helps to know what this word means.
If you go to the passage (on the page marked 440 in the packet), you see that they define this term in the first paragraph. Specifically, the definition is given in the first sentence: "The idea that life did not originate on earth, but was carried here either deliberately or by natural processes..."
From this first paragraph, the second paragraph highlights reasons people were less llikely to accept the idea of "panspermia" being possible. ARGUMENTS AGAINST-->
+) Interstellar space has ultraviolet radiation and cosmic rays (see paragraph 2)
+)Meteorites are subjected to burning temperatures when entering Earth's atmosphere. (This wasn't in your list, but was part of the original question. They discuss the heat in paragraphs 3,4, and 5. The ideas of heat and overcoming this is woven into both arguments and how they are showing ways to overcome. If you have trouble finding this, however, I can help you find specific sentences...).
+) Distances in interstellar space are huge (Paragraph 2)
The third and fourth paragraphs then discuss ways the objections to "panspermia" could be overcome, therefore supporting the possibility of a "panspermia." SUPPORT FOR-->
+) Stars with a repulsive force greater than their attractive force are able to eject material (This answers the question raised in the 3rd sentence of paragraph 2. This response is found in paragraph 3).
+) Bacterial spores have been shown capable of surviving for several years in space (The final sentences in paragraph 4 give us evidence of this: "As for the long journey..." is how one such sentence starts.).
+) Prebiotic chemicals exist in comets. (See the fifth paragraph and the mention of Halley's Comet).
+) Comets are made up of water and other material (See the final sentence of paragraph 3...)
The 3 Unused Sentences-->
The fourth paragraph has a parenthetical comment that many people reject the possibility of the meteorite in Antarctica countaining frozen Martian fossils, so the comment: "+) The meteorite found in Antarctica contained frozen fossils" can become one of the three unused statements.
+) Bright stars emit a lot of ultraviolet radiation --> There is a mention of the problem of radiation in paragraph 2, when giving a reason why "panspermia" seems unlikely. In the fourth paragraph it says: " Such ejecting stars cannot be too luminous since brighter stars emit too much ultraviolet radiation for the survival of bacteria." However, this is just saying that there is a limitation in regards to the type of star from which the material /life may be ejected, since the bright stars would present too much radiation. This is not an argument about why "panspermia" could never occur, however.
It is a trick question to make this difficult (in addition to any of the difficulty of the reading itself), since there is a common thread between the mention of the overall problem of radiation for the idea of "panspermia," as mentioned in the 2nd paragraph's objections to this concept, and this mention about the radiation of bright stars.
Not all stars are equally bright, however, so the bright stars giving off radiation wouldn't be the reason why "panspermia" seems unlikely, since if that was the only radiation issue, then the process could perhaps otherwise exist far from the bright stars. Instead, the second paragraph mentioned a larger issue of the radiation and cosmic radiation of interstellar space (which is a much larger issue and more applicable to inhibiting such a concept, since this encompasses more than just bright stars.) I hope this somewhat makes sense...
+) Meteorites from Mars have been found on Earth in areas of Antarctica where the cold temperatures protected life-forms -->This feels like one that one might want to pick, due to all the mention of the meteorite and the temperature in the mediate being low enough, etc. However, the way this statement is worded is the real problem. From the way that this is wordedm there seems to be the argument that the cold temperatures in Antarctica were responsible for protecting life-forms. This isn't directly talking about core temperatures in the meteorites or anything specific to the meteorite, as opposed to the continent of Antarctice, which is known for its intense cold.
I hope this helps. Please reach out with any questions. If any of this is hard to follow, we can perhaps try a video response, or follow-up responses to clarify anything that may seem unclear.
Take Care :)
