Final answer:
To simplify an IPv6 address, you can compress any single series of consecutive zeroes into a double colon (::), but only once to prevent ambiguity.
Step-by-step explanation:
In IPv6 addressing, the zero-compression rule allows for the reduction of an address by omitting consecutive sections of zeros. However, this can only be done once in an address to prevent ambiguity. Therefore, you can remove all zeros in a consecutive series of sections and replace them with a double colon (::), but only for one such series. This means that if you have multiple sections of zeroes, you must choose the longest and/or most strategic series of zeroes to omit. The answer to the question 'How many zeroes can you remove to leave only a single 0 in an IPv6 address?' is that it's not a matter of how many zeroes you remove, but rather that you compress them into one set represented by '::' and can do this for one set of zeroes only.