The phrase "are normally low" is correct and usable in written English.
It can be used to describe a general condition or state that is typically below a certain level or standard.
Example: "The temperatures in this region are normally low during the winter months."
Alternatives: "tend to be low" or "are usually low".
Pulmonary-artery pressures are normally low compared with those in the aorta.
Although nuclear materials naturally emit characteristic radiation (e.g. neutrons, γ-rays), their intensity and energy are normally low.
For drugs that require interaction with cellular machinery, the efficacies of both macroscopic and microscopic delivery systems are normally low.
p21 protein levels are normally low, however in response to DNA damage, p53 activates transcription of the gene encoding p21 and hence increases p21 protein levels.
The addition of the proteasome inhibitor MG132 increased levels of β-catenin as well as that of phospho-β-catenin (Figure 5A, lane 2), consistent with the notion that β-catenin levels are normally low because of proteasomal degradation upon phosphorylation by GSK3.
In highlands, transmission is unstable due to fluctuations in temperatures that are normally low (2 ).
School-budget ballots are normally low-turnout affairs, and therefore dominated by the teachers themselves.
The yield of the crop is normally low because of insufficient moisture in the soil.
This illness is rare in people with healthy immune systems, and demand for pentamidine was normally low.
Residents are reinforcing sliding doors, locking windows during the day and pooling money to start patrols in an area where crime is normally low.
Expression of CD24, a marker of luminal differentiation that is normally low expressed in BCSCs, was significantly increased 10 days after miR-34a induction (Supplementary Fig. 5c).
