Page 2: Considering the following sentence: "Experimentally RTFM has been observed in undoped MgO nanoparticles preferable synthesized by wet chemical routes", complete with: (see Table 1) A3: CORRECTED. 4) Page 2: Please, explain what the Author mean when they say: "the surface of such nanoparticles was not sufficiently clean" A4: CORRECTED as: "the surface of such nanoparticles could not sufficiently clean compared with NPs produced by gas-phase methods." Q5) Page 3: Substitute "metal magnesium" with "metallic magnesium" A5: "metal" is corrected to "metallic". 6) Page 4: Please, specify better the techniques that are used to evaluate the parameters listed in Table 2, or move the Table in the "Results and discussion" section A6: In page 4 the text was corrected as: "Some parameters of the NPs synthesis, including metal feed rates, gases flow rates, and corresponding collection zones are listed in Table 2. Table 2. Main properties of the Mg-O NPs. S-specific surface area obtained from BET measurements; -mean particle size obtained from SEM micrographs; y-MgO content and a-MgO lattice parameter obtained from XRD data; σ s-maximum specific magnetization (VSM, RT, 10 kOe)." 7) Page 5: As concerns the BET measurements, specify the measurements conditions (i.e., time, temperature, minimum pressure in outgassing procedure) A7: In the text on page 5 was added the sentence: "No outgassing procedures were applied before the BET measurements." 8) Page 6: Correct: "collected in the main zone" with "collected in the main zones" A8: CORRECTED. 9) Page 6: Considering the sentence: "In Figure 2a, NPs of about 50 nm in an average size is generally uniform cubes", please specify how the Authors evaluate the average size. From a first visual investigation, only the interval can be estimated. A9: In the text on page 5 written: "Particle size and morphology were investigated by scanning electron microscopy (SEM) using CARL ZEISS ULTRA PLUS. Electron micrographs were analyzed by Carl Zeiss AxioVision ver. 4.82 image processing software to calculate the average particle size ‹d› [22]." 10) Page 6: Author refer to the "Particle size distribution", but it is not reported. Did the Author evaluate the particles size distribution by SEM images? A10: Yes, see A12.