Questions

We know that, the nucleotide in DNA is of the form deoxyribose + phosphate group + polymerase.

Hence, Deoxyribose + Phosphate Group + Thymine is the only option in that form of nucleotide in DNA.

Allotropes are the different physical forms of an element. Here in the given options, diamond and graphite are the pair of allotropes of carbon.

Some more examples are Molecular oxygen and ozone are pair of allotropes, Black and red phosphorous are also pairs of allotropes.

ROM cannot be used as stack because it is not possible to write to ROM.

India's first passenger train run took place from Mumbai to Thane for around 34 kms on 16th April in the year 1853. 

That train was hauled by three steam locomotives : Sahib, Sindh and Sultan.

That train had 14 carriages, carrying around 400 passengers.