A graduate student filtered a liter of seawater using a Millipore filter membrane of 2 mm pore size. Her filtrate
A) is sterile.
B) contains microplankton.
C) contains picoplankton.
D) contains nanoplankton.
E) contains all plankton.

Question

Quizplus · Accepted Answer

The Millipore filter membrane of 2 mm pore size is capable of capturing particles with a size of 2 mm or larger. As picoplankton is typically smaller than 2 mm in size, it would pass through the filter and be present in the filtrate. The filtrate may still contain other larger plankton sizes such as microplankton and nanoplankton, but it is certain to contain picoplankton. Option A is not a definitive statement and cannot be concluded from the information given. Option E is too broad and not specific enough. Option B and D are not necessarily true as the filter may not have captured all microplankton or nanoplankton.

A Graduate Student Filtered a Liter of Seawater Using a Millipore