Paragraph one defines lichen and cites a new DNA study shedding light on the evolutionary origins of lichen. Paragraph two describes the symbiotic relationship that constitutes kitchen - fungi & algae - and associated research challenges and proceeds by providing further details regarding new research that successfully isolated fungi DNA sequence using new analytical tools. Paragraph three describes the implications of the aforementioned research, challenging a longstanding evolutionary assumption that parasitic interactions evolve over time.
Let's look at (C) & (D).
(C) "definition of lichens; discussion of the difficulty in classifying their fungal components; resolution of this difficulty and implications of the resulting research"
(D) "discussion of the symbiotic relationship that constitutes lichens; discussion of how new research can distinguish parasitic from symbiotic fungi; implications of this research"
(C) is a better description of the passage for several reasons: (1) the passage starts off with a short definition "a lichen consists of a fungus living in symbiosis with alga," there is no discussion of this relationship, at most, we could call it a description; (2) the objective of the new research is to classify lichen-forming fungi within the fungus family tree rather than 'distinguish parasitic from symbiotic fungi" as (D) suggests. The passage merely tells us that researchers were able to successfully isolate DNA in "parasitic or symbiotic" relationships (lines 32-35) and use this DNA to establish the relationship between litchen-forming and other types of fungi. Since this is an inaccurate summary, we can eliminate (D).
Does this make sense?
Let me know if you have any further questions.
alvaon August 13, 2019
Yes it does thank you
shunheon February 1, 2020
@alva, Glad it helped! Feel free to ask any other questions that you might have.
