Taj Mahal is slowly losing its white color because of pollutants from vehicles and industries around it. It is a result of chemical weathering. Polluted air contains a large amount of nitrogen and sulfur oxide released from the industries in the area.
These chemical comes down with the rain and called acid rain. This acid rain reacts with the marble which is made up of calcium carbonate thereby turning the Taj Mahal yellow.
These environmental pollution cause the oxidation of marble constituents from which Taj Mahal is made up of and are responsible for the chemical weathering of Taj Mahal.
Chargaff base pairing rule state that the ratio of purines to pyrimidine in a specific DNA from any cell or specie must be equal in 1:1 ratio. In chargaff base pairing rule Cytosine C will pair with Guanine G on the complementary strand and Adenine A will pair with Thymine T on the complementary strand. C=G, A=T
So if the sequence 5' CGGCTAATCGCC 3' on the complementary strand will be
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