## 4 Discussion  
This is a continuation of a previous study that clearly showed changes in the biophysical properties of water, which are determined through the effect of a CMF [11]. That study demonstrated that water incubated at the CMF enhanced ROS production by neutrophils. To find out which mechanism underlies the action of a magnetic field to change the ability of water samples to stimulate neutrophils to produce ROS (in our case, this is the CMF of 12.6 Hz 50 nT along with the SMF of 60 nT), additional experiments were required. Currently, there are different opinions on this issue: the ability of water after exposure to the CMF to enhance ROS production by neutrophils can be associated with \"cyclotron\" resonance [18] or be the consequence of the correspondence of the AMF frequency to the magnetic moments of protons in molecules [13; 19; 20], in clusters or hydrated ions, or other general physical mechanisms [21; 22; 23]. This assumption is supported by works on changes in the refractive index under conditions of weak magnetic fields [24], as well as studies defining water as a tunable oscillator [18]. Naturally, to confirm this hypothesis, in addition to the assessment of biological response, measurement of corresponding physical characteristics will also be required. However, it seems that the form of experimental dependence of ROS production by neutrophils from parameters of the SMF (frequency or the magnitude), as well as the dependence of the effect on the magnitude of the variable component of the magnetic field, may be decisive in determining the activity of water incubated under such magnetic fields. In this work, we show that the presence of magnetic fields is necessary for maintaining the ability of water dilutions to enhance ROS production by neutrophils. At values close to the GMF, namely at an SMF of 20,000 nT, the measurement results did not differ from those at the GMF. At the same time, when the SMF component was changed to near-zero values, the activity of samples pre-exposed at this field did not differ from the controls (intact water). For example, in the case of C12, samples with minimum or maximum values of the SMF (10 nT and 20,000 nT) differed the most. The C50 samples showed more pronounced differences at medium fields of about 900 nT. This means that the different dilutions are not identical in terms of biophysical properties. Thus, the experimentally determined values of the \"maintaining\" magnetic field (in our case, it is the SMF in the range of a weak \"hypomagnetic\" field) can be useful for determining specific magnetic moments involved in the formation and retention of the activity assessed. It has been established that the dynamics of a single magnetic moment relative to a selected direction set by its local chemical environment can be altered using an external magnetic field [21; 22; 23]. The most significant changes in the dynamics of magnetic moments can occur exactly at the \"zero\" magnetic field conditions, when the energy between the split Zeeman sublevels of magnetic moments becomes extremely small [21; 22; 23]. There are a few possible targets possessing a magnetic moment: an electron (with spin and orbital magnetic moments), the magnetic moment of a proton, and other magnetic nuclei (e.g., C13, N15, etc.). The gyromagnetic ratio and lifetime of all these potential targets of the magnetic field effect differ significantly and are often known for different molecular environments. The experimental dependence of ROS production by neutrophils at a near-zero magnetic field, which we documented in detail, may be sufficient for the successful calculation and determination of the field target responsible for the specific magnetic effect we identified. It is possible that the patterns discovered in our work are also applicable to HDs of not only water but also various substances in low concentrations.