Genetics is the study of inheritance and variability in life including genes, genetic materials, genetic code, genetic information in the code, expression of the genes or genetic information and understanding the generation and inheritance of variations (mutations). Besides, it also studies physical, chemical and biological nature of the genomes as arrangement of genes, genotype and their interaction the environment to be expressed into a certain phenotype. A particular organism may possess alternate forms of one or more genes known as alleles and leads to genetic polymorphism. Genome (the whole DNA or sometimes RNA) is stored in form of chromosomes, which are chains of double stranded DNA in all living being except the virions which may also posses other forms of genome made of ssRNA, dsRNA, ssDNA. Within DNA, genes exist as sequences of nucleotides which code for functional proteins. The genetic material of bacteria and plasmids is dsDNA but of bacteriophages it may be dsRNA, dsDNA, ssRNA, or ssDNA. Two essential functions of genetic material are replication and expression in all organisms. The subject is made easy to understand through question and answers in simple English.