According to the passage, the elimination of which one of the following obstacles enabled scientists to identify the ...

Skylar on October 5, 2019

@Lucas Happy to help!

The question asks "According to the passage, the elimination of which one of the following obstacles enables scientists to identify the evolutionarily origins of lichen-forming fungi?"

Starting in line 19, the passage explains that "lichen-forming fungi are especially difficult to study...and they are unusually difficult to isolate from their partner algae, with which they have a particularly delicate symbiosis." This identifies the main obstacle to the further study of lichen-forming fungi - separating DNA of the fungi from the algae.

Beginning in line 32, however, we see a change. The passage reads "But, using new analytical tools that allow them to isolate the DNA of fungi in parasitic or symbiotic relationships. researchers were able to establish the DNA sequence....Based on these analyses, the researchers found 5 branches on the fungus family tree to which varieties of lichen-forming fungi belong." So, here the passage discusses overcoming the obstacle of separating DNA of fungi from their connected algae, which then allowed scientists to identify origins of the fungi (i.e. their family tree).

Therefore, answer choice (A) "the DNA of lichen-forming fungi was not easy to separate from that of their associated algae" is correct and directly supported by information given in the passage.

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