The phrase "are mostly distributed in" is correct and usable in written English.
It can be used when describing the general location or spread of something, such as populations, resources, or data.
Example: "The species are mostly distributed in tropical regions, where the climate is suitable for their growth."
Alternatives: "are primarily found in" or "are mainly located in".
(a) Diameter distribution from HRTEM observations, demonstrating that the diameters of the SWCNTs are mostly distributed in discrete steps which correspond to multiples of the BN (002) interplanar spacing.
In K. arvensis, the species with the widest distribution area [ 36], our geographically limited sample showed that diploids are mostly distributed in the inner part of the Alpine arch, whereas tetraploids extend from its outer margin towards the northeast and southeast, with one population (K126) also in the Kvarner Bay of the northern Adriatic.
These rangelands are mostly distributed in Inner Mongolia, Xinjiang, Ningxia, and the Qinghai-Tibet plateau6.
They are mostly distributed in humid forest or savannah equatorial zone.
They are mostly distributed in the middle myocardium and run circumferentially.
Fractures are mostly distributed in fracture zones along the fault zone.
Haplotype F (1058 bp, freq. 7%) was mostly distributed in the western edge of the unisexual distribution.
The geothermal gradients thus obtained were mostly distributed in the range of 20 40°C/km (Fig. 8), the distribution pattern of which closely matches the measured data of Tanaka et al. (2004), although the present result is generally lower than the measured values.
In addition, R8-LP was mostly distributed in liver, spleen and lung, whereas CL-R8-LP and PEG-LP distributions in these organs were decreased significantly (Fig. 5B).
The mass of plastics floating in the GPGP was mostly distributed in macro- and megaplastics.
The exception to the rule was the former top newspaper, USA Today, which is mostly distributed in hotels.
