Consider the following statements : 1. Adenoviruses have single-stranded DNA genomes whereas retroviruses have double-stranded DNA genomes. 2. Common cold is sometime caused by an adenovirus whereas AIDS is caused by a retrovirus. Which of the statements given above is/are correct?

States that viruses are acellular entities that multiply only inside living cells, implying they carry some form of genetic material to direct replication.

A student could combine this with the external fact that different viruses carry either DNA or RNA genomes and then look up whether adenoviruses are DNA or RNA viruses and whether their DNA is single- or double-stranded.

Explains DNA copying as a fundamental biological process and treats DNA as the molecule that stores genetic information in reproducing entities.

Using this general rule, a student can reason that if adenoviruses rely on host machinery to replicate, identifying their nucleic acid type (DNA vs RNA) and structure (single vs double strand) would determine how replication proceeds.

Describes DNA organized into chromosomes in cellular organisms, illustrating that biological genetic material can have defined structural organizations.

A student could use this pattern (genetic material has characteristic structures) and external virology references to compare viral genome organizations (e.g., chromosomes vs viral nucleic acid forms) and thereby investigate adenovirus genome strandness.

Defines viruses as acellular agents that multiply inside living cells, indicating viruses are a distinct class of genetic entities whose genomes can differ from cellular genomes.

A student could combine this with external knowledge that viral genomes vary in type (DNA or RNA, single- or double-stranded) to question whether retroviruses necessarily carry DNA genomes.

Explains that cells create copies of DNA, producing two DNA copies in a reproducing cell — highlighting the common cellular pattern of double-stranded/duplicated DNA during replication.

One could contrast this cellular DNA-copying pattern with viral replication strategies (from external sources) to see whether retroviruses follow cellular double-stranded DNA norms or use other molecular mechanisms.

Describes genetic material in organisms as organised into chromosomes (separate DNA pieces present in pairs), establishing a pattern of genomic DNA organisation in cells.

A student can use this to note that cellular genomes are double-stranded DNA organised into chromosomes and then ask whether viral genomes (retroviruses) share that organisation or differ (requiring outside reference).

Mentions parents passing genetic material as halves in gametes, reinforcing the idea that cellular heredity uses DNA as the genetic molecule transmitted in specific forms.

From this, a student might infer that 'DNA is the hereditary molecule in cells' and then seek external information on whether retroviruses use DNA or another nucleic acid as their genomic material.

Discusses accumulation and combination of variations in DNA copies across generations, emphasizing that biological information is typically DNA-based in organisms.

A student could use this to frame a comparison: since organisms use DNA for heredity, do viruses (specifically retroviruses) also have DNA genomes or do they employ different strategies (to be checked externally)?

Lists the common cold as a disease whose causal agent is 'Virus' and that infects the respiratory tract.

A student could take this general rule (common cold = viral respiratory infection) and check external lists of viruses known to infect the respiratory tract to see if adenoviruses are included among causes of common cold.

Defines viruses as acellular agents that multiply inside living cells and may cause disease in animals, implying that various virus types can cause respiratory illnesses.

Use this definition plus knowledge that adenoviruses are a virus family to investigate whether members of that family infect human respiratory cells and can produce cold-like symptoms.

Explains that communicable diseases can spread through the air when an infected person coughs or sneezes — the typical transmission route for many respiratory viruses that cause colds.

A student can combine this transmission pattern with external data about adenovirus transmission to assess whether adenoviruses plausibly spread and cause respiratory (cold) illness.

Gives a concrete example of a virus (SARS-CoV-2) affecting the respiratory system, illustrating that different viruses can cause a spectrum of respiratory diseases.

By analogy, a student could look up whether adenoviruses are documented to infect the respiratory tract and produce mild (cold-like) versus severe disease.

Describes how the respiratory tract (cilia, alveoli) defends against inhaled germs and how damage increases susceptibility to infections, relevant to how viruses cause respiratory symptoms.

A student could consider host factors affecting susceptibility and then check whether adenovirus infections manifest as upper respiratory (cold) symptoms under normal or predisposed conditions.

Explicitly states AIDS is caused by the human immunodeficiency virus (HIV), establishing the etiologic agent is a virus.

A student could note HIV is a virus and then check external virology references to see whether HIV falls into the retrovirus group.

Describes HIV's mode of action (slowly attacks/destroys the immune system and targets helper T cells), which is consistent with persistent viral infections that integrate into immune cells.

A student could use this pattern (virus targeting immune cells) plus basic virology sources to investigate whether such behaviour is characteristic of retroviruses and whether HIV shares those properties.

Classifies HIV-AIDS among viral infections in the context of sexually transmitted diseases, reinforcing that the causative agent is a virus rather than a bacterium or protozoan.

Knowing HIV is a virus, the student can consult standard virology texts or reference sources to determine the subclassification (e.g., retrovirus).

Defines pathogens to include viruses and notes diseases can be caused by viruses, giving a general rule that viral identification matters for determining disease class.

A student could apply this general rule to treat the claim 'AIDS is caused by a retrovirus' as a specific viral-classification question and look up HIV's virus family externally.

Mentions other named viruses (e.g., ebola) in the context of emerging diseases, showing these texts distinguish diseases by specific virus names and types.

A student could infer that since the textbook distinguishes viruses by name/type, they should consult authoritative virology classification resources to see whether HIV is categorized as a retrovirus.