Adenine base is present in which of the following?

How are nucleotides linked together in nucleic acids?

In the double-strand helix structure of $DNA,$ thymine forms hydrogen bonds with

The pyrimidine bases present in $DNA$ are

Which base is present in $RNA$ instead of $Thymine$?

Fill in the blanks:
$(1)$ Genetic information containing molecules is known as ........
$(2)$ The formulas of ammonium cyanate and urea are ........ and ......... respectively.
$(3)$ The hybridisation type of carbon in methane,ethane,ethene,and ethyne is ..........,.........,......... and ......... respectively.
$(4)$ From $sp^3, sp^2$ and $sp$ hybrid orbitals,....... is most and ......... is least electronegative.