It comprises several muscle parts that are often difficult to discern and which have, over the years, been given several names, making understanding even more difficult.
Human contamination is difficult to discern in eukaryotic DNA, because there is an over whelming bias of human DNA sequences in the databases.
In advanced disease, it may be more difficult to discern the contribution of VTE to mortality over and above that of cancer.
The prices charged by physicians, hospitals, labs and others are all over the map and difficult to discern in advance.
Particularly, the physical alterations of the paint surface mainly caused by discolored varnish, retouches and overpaints as well as over-cleaning areas and paint losses, made it difficult to discern the artwork's original artistic quality.
But part of the Greek text was always difficult to discern, and the obelisk's exposure to the British climate over the past 200 years has only made that task more difficult.
Systematic changes in PCB levels are difficult to discern, due to a paucity of data and analytical differences over the years.
Although over the last decades it often has been difficult to discern whether Republicans were more opposed to liberalism than authoritarianism, in the last few months they have clearly recalibrated to make it clear that they are.
Delusions tend to be infectious, infusing the over-valuations of general tech startups into the food community, making it difficult to discern whether a food-delivery service has a solid value proposition or if the technology itself is overhyped.
The track consists of over-the-top vocal distortions, causing a split sound effect, making it difficult to discern which voice is Spears'.
