Final answer:
The correct and unique choice for naming covalent compounds is that their names use Latin prefixes to indicate the number of atoms present in the formula.
Step-by-step explanation:
Among the choices provided for naming covalent compounds, the option that is both true and unique is that covalent compound names use Latin prefixes to indicate the number of atoms in the formula. This naming convention applies to covalent compounds to reflect the exact number of atoms of each element present in the compound, such as 'mono-' for one, 'di-' for two, 'tri-' for three, etc. It is important to note that the prefix 'mono-' is typically not used for the first element if there's only one atom of it. For compounds with two elements, the second element's name ends with the suffix '-ide'. Meanwhile, Roman numerals are used to show the oxidation state of metals in ionic compounds, not for indicating the number of atoms in covalent compounds' names.