1.The main difference between Nucleotide and Nucleoside is very crucial to understand the key differences between the two. They are building blocks of nucleic acid, as nucleotides consist of the same components such as a nitrogenous base, sugar and a phosphate group. The main difference lies in their molecular composition as Nucleosides contain only sugar and a base whereas Nucleotides contain sugar, base and a phosphate group as well. A nucleotide is what occurs before RNA and DNA, while the nucleoside occurs before the nucleotide itself.

2. central dogma is the process o making DNA from protein.

3.DNA replication is said to be semi-conservative because of this process of replication, where the resulting double helix is composed of both an old strand and a new strand. Semiconservative replication would produce two copies that each contained one of the original strands and one new strand.

4.A codon is a sequence of three DNA or RNA nucleotides that corresponds with a specific amino acid or stop signal during protein synthesis. DNA and RNA molecules are written in a language of four nucleotides; meanwhile, the language of proteins includes 20 amino acids.

5.Genotype refers to the genes responsible for a trait, phenotype is the visible result of those .

here brown hair is phenotype and the gene which makes the hair brown is called genotype.