AP BIOLOGY

Detailed explanation-1: -Baltimore classification (first defined in 1971) is a classification system that places viruses into one of seven groups depending on a combination of their nucleic acid (DNA or RNA), strandedness (single-stranded or double-stranded), sense, and method of replication.

Detailed explanation-2: -Overall, DNA viruses are in groups I and II, RNA viruses are in groups III, IV, and V, and reverse transcribing viruses are in groups VI and VII. Viruses with a double-stranded DNA genome are classified under Group I. Viruses with a single-stranded DNA genome are within Group II.

Detailed explanation-3: -Viruses are classified on the basis of morphology, chemical composition, and mode of replication.

Detailed explanation-4: -Viruses were initially grouped by shared morphology. Later, groups of viruses were classified by the type of nucleic acid they contained, DNA or RNA, and whether their nucleic acid was single-or double-stranded.

Detailed explanation-5: -Baltimore classification is a system used to classify viruses based on their manner of messenger RNA (mRNA) synthesis. By organizing viruses based on their manner of mRNA production, it is possible to study viruses that behave similarly as a distinct group.