(Need the answer as soon as possible.) "Scientists are not sure whether the microbes come
from the seawater surrounding the vents or from deep
inside Earth beneath the vents, but they appear as fuzzy
white material on the seafloor near the vents."
(Paragraph 5)

How does this scientific uncertainty most affect the
passage?

1. It provides a possible reason why microbes can
withstand toxic chemicals.

2. It suggests a theory about why microbes tend to
thrive near hydrothermal vents.

3. It casts doubt about the microbes' function as
producers in the deep-ocean food web.

4. It shows the need for further research to
determine the significance of the microbes
origins.

(No links)