Question

text 1
sidebells wintergreen (orthilia secunda) plants are native to alaska,
where harsh conditions have historically impeded potential invasive
species. as the boreal climate has warmed in recent decades,
however, siberian peashrub (caragana arborescens) plants have
established themselves in alaska. previous research conducted in
non - boreal ecosystems has documented warming - induced increases
in summer temperatures benefiting invasive species more than native
species.
text 2
at a site near fairbanks, alaska, christa mulder and katie spellman
tracked o. secunda and c. arborescens, along with other native and
invasive species, over several years. they observed that although
average summer temperatures were substantially higher in some
years of the study than in others, neither o. secunda nor c.
arborescens showed any significant variation in summer growth
patterns from year to year.
a. text 2 describes a methodology that helps researchers avoid a
problem encountered in the studies discussed in text 1.
b. text 2 explains a study that suggests an alternative explanation for
the trend observed in the research discussed in text 1.
c. text 2 discusses an observation that challenges the validity of the
findings described in text 1.
d. text 2 presents a finding that casts doubt on the generalizability of
the research discussed in text 1.

Explanation:

Text 1 mentions that previous research in non - boreal ecosystems shows warming benefits invasive species more. Text 2 is a study in a boreal area (Alaska near Fairbanks) where the result (no significant variation in growth patterns of native and invasive species with temperature changes) is different from the non - boreal research. This shows that the non - boreal research may not be applicable (generalizable) to the boreal area.

Answer:

D. Text 2 presents a finding that casts doubt on the generalizability of the research discussed in Text 1.