Final answer:
An ohmmeter will measure zero ohms across all branches of a parallel circuit with power removed if it is short-circuited, because the undesired low-resistance path effectively bypasses other components.
Step-by-step explanation:
With power removed from a short-circuited parallel circuit, an ohmmeter will measure zero ohms across all the branches. This is because a short circuit is defined as an undesired path of low resistance which effectively bypasses other components in the circuit, leading to nearly no resistance measurement. It's important to understand that in a parallel circuit, the total resistance is always less than the resistance of the smallest resistor due to the multiple paths available for the current to flow. However, in the case of a short circuit, the resistance becomes so low that it is effectively zero, which is not the normal operating condition for a circuit and can lead to excessive current that risks damaging the circuit components or causing a fire hazard due to rapid thermal power generation, as exemplified by P = V²/r where r is the resistance.