The phrase "are differing levels of" is correct and usable in written English.
It can be used when discussing variations or distinctions among different categories, qualities, or quantities of something.
Example: "In the study, we found that there are differing levels of engagement among students based on their learning styles."
Alternatives: "varying degrees of" or "different levels of".
One possible explanation may be differing levels of oestrogen in women, with earlier stage tumours having been associated with the use of hormonal therapy (Chlebowski et al, 2004).
While largely unknown, it is likely that there are also differing levels of validity and reliability across the range of these assessments.
Alternatively, the inconsistencies may be due to the differing periods over which exposure was assessed, differing levels of water nitrate across studies, or differences in exposure to other cofactors.
These differences are thought to be generated by differing levels of testosterone exposure before birth.
Variation is assumed to be due to differing levels of efficiency, but may in fact be due to other possible causes including epidemics, natural disasters, missing or erroneous data, or local socio-economic conditions.
Sixth, the intelligence must be measurable in psychometric studies that are reflective of differing levels of mastery across intelligences.
Since no genes that function in alternative splicing regulation, such as SR protein family genes, have been found in E. cuniculi, we suggest that variation in intron motif features are responsible for differing levels of intron retention within a gene.
The reasons for this are not clear, but may be due to differing levels of taxon sampling in and near this part of the tree, outgroup choice (although tests of different grass outgroups here had no effect on the ingroup topology) or varying phylogenetic signal in different partitions of the data [as demonstrated for monocots in Davis et al. (2013), for example].
