The present work reviews the facts of some models related to the dark matter and energy with variation of gravitational and cosmological constants with the cosmic time by giving the evidence in support of expanding universe due to Big Bang. Three important time epochs of BBN like Inflationary era, Radiation dominated era and Matter dominated era have also been discussed. The paper discusses also about the age of the universe using Hubble law in terms of Hubble constant and density parameter including the concept of space-time, geography of the universe, new cosmology, dark energy and some challenges and says that the correct theory of gravity is massive scalar-tensor gravity drawn from the detection of the gravitational wave from the collision of binary black holes as predicted by Albert Einstein's general theory of relativity, 100 years ago.

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Complex of Cu(II) with bis-(3,5-dimethyl salicylidine)-ethylenediamine was synthesized and characterized by elemental analysis, melting point determination, conductivity measurement, magnetic and spectroscopic studies. Molecular formula of the newly prepared complex was determined as C20H22N2O2Cu and the probable geometry has been suggested as square planar. Gravimetric estimation of Cu(II) was made with bis-(3,5-dimethyl salicylidine)-ethylenediamine and the result was compared with the known method of estimation of Cu(II) iodometrically. It was found that the result of estimation with newly prepared reagent was as good as the reported result of estimation of Cu(II) iodometrically.

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