The phrase "are mostly subject" is correct and usable in written English.
It can be used when discussing conditions or situations that are generally influenced or governed by certain factors.
Example: "The results of the experiment are mostly subject to the variables we controlled during the study."
Alternatives: "are primarily influenced" or "are largely dependent".
The upper (down to 2000 m water depth) and lower (down to 3700 4600 m water depth) slopes are mostly subject to different types of slope failures, such as slides, mass-transport deposits (a mix of slumping and mass-flows), and turbidity currents.
Comparative studies have repeatedly shown that pseudogenes, which have been so defined because they lack coding potential due to the presence of disruptive mutations, evolve very rapidly and are mostly subject to no functional constraint (Pei et al. 2012).
It's very slow, though it does offer a respite from the overactive animation that kids are mostly subjected to.
Moreover, it is based on uniaxial tests whereas the real structures are mostly subjected to combined loadings.
The swamps were mostly subject to ecological stasis during early and middle Westphalian times, although they contracted locally in response to drying of substrates.
And those tour-stunted artists who did use "exhaustion" as a vague pretext were mostly subject to Twitter diagnosing them with mental illness anyway.
The design of nuclear fuel, which is mostly subjected to loads due to high temperature, pressure and flow under radiation environment, is of immense importance in nuclear engineering.
In total, the organisation was mostly subjected to policy instruments that pushed HIV/AIDS issues in two periods; the beginning and mid 1990s, and later in the final years of the decade.
The index cases of our sample were, mostly subjects enrolled in Clinical Research trials of TB in our TB Clinic and were people from the community and with no initially known risk factors for TB.
After all, the numbers involved are mostly estimated, subject to change once the season gets under way; for instance, there are escape clauses enabling agencies to relinquish commercial time they bought in the upfront market if clients change their minds about needing the spots during the season.
Hidden tax-haven assets are mostly illicit and subject to back-tax interest and penalties, which makes HMRC's target for collection £2tn or three years' UK budget.
