in case you don't know how:
you can set your tumblr private by going to "settings" below "customize appearance" from your dashboard. scroll down to the bottom and tick the box where it says "password protect this blog"
Nucleotide is basically the basic building blocks of either DNA or RNA
A nucleotide is the basic building block of nucleic acids. RNA and DNA are polymers made of long chains of nucleotides. A nucleotide consists of a sugar molecule (either ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen-containing base. The bases used in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). In RNA, the base uracil (U) takes the place of thymine.