Comparison of the thermal gradient and radiofrequency on the spread of Covid-19 and proliferation of zebrafish.

We present and discuss how specific weather factors are responsible for COVID-19 transmission. The heavy spread of the COVID-19 pandemic worries humanity. We analysed the incidence of COVID-19 as a function of latitude and in particular on the temperature differences during the morning up, and in the afternoon down, and other factors that justify the spread of the pandemic in the world and in Italy. The studies on the spread of Covid-19 were conducted in 2021. The pandemic peaks as a function of latitude are around $-25\,(^{\circ})$ and $+50\,(^{\circ})$ which are disjoint from only temperature. Similar results are also confirmed in 2022. But today the heart is invaded by radiofrequency. So different electromagnetic generators were made to stress zebrafish ({Danio $rerio$) embryos. The stress was operated by static, low frequency magnetic and radio frequencies fields. Embryos were exposed to static, very low frequency, low frequency, very high frequency and ultra-high frequency field irradiations. Untreated embryos were used as control and their survival was 60%. Survival of zebrafish larvae at 5 days after exposure to magnetic fields and radiofrequencies reached up to 80% when static, 0.2 Hz magnetic field, or 100 MHz electromagnetic field are used. This result is an excellent result that allows us to improve the development and spread of species.