Genome is the total genetic information of an organism. For most organisms, it is the complete DNA sequence. For RNA viruses, the genome is the complete RNA sequence, since their genetic information is encoded in RNA.
a. 1 Mb = 1 million base pairs (for double-stranded DNA or RNA) or 1 million bases (for single-stranded DNA or RNA).
b. The human genome contains about 21,000 protein-coding genes and 18,000 RNA genes.