Which one is not a correct definition? a. An enveloped virus have more advantages then naked viruses b. Enveloped viruses are more sensitive to environmental conditions c. Viruses'genetic material can be either DNA or RNA d. Viral nucleic acid is always surrounded by capsid __ __

The correct answer is d. Viral nucleic acid is always surrounded by capsid.<br /><br />Explanation:<br /><br />a. An enveloped virus has more advantages than naked viruses: This statement is generally true. Enveloped viruses have a lipid bilayer membrane that surrounds their capsid, which provides them with increased stability and protection from environmental factors. The lipid membrane also allows for the incorporation of viral glycoproteins, which are essential for the virus to attach to and enter host cells.<br /><br />b. Enveloped viruses are more sensitive to environmental conditions: This statement is also true. Enveloped viruses are more susceptible to environmental conditions such as heat, desiccation, and detergents because their lipid membrane is more easily disrupted compared to the protein capsid of naked viruses.<br /><br />c. Viruses' genetic material can be either DNA or RNA: This statement is true. Viruses can have either DNA or RNA as their genetic material, which can be either single-stranded or double-stranded. The genetic material can be linear or circular, and it can be either positive-sense (same sense as mRNA) or negative-sense (complementary to mRNA).<br /><br />d. Viral nucleic acid is always surrounded by capsid: This statement is not correct. While the viral nucleic acid is always enclosed within a protein capsid, it is not always surrounded by it. In some viruses, the nucleic acid is encapsulated within a complex protein structure called an "envelope," which is derived from the host cell membrane and contains viral glycoproteins. Therefore, the viral nucleic acid is not always "surrounded" by a capsid, as it may also be enclosed within an envelope.