Answer:
A key field is used to uniquely identify each record for retrieval or manipulation.
Explanation:
In a database there are many, having similar entities. So in order to differentiate each entity from other we need to set a key field among all the field which is always unique for each entity.
For example:
In a database of a company having data about its employees, the key field might be their ID. As some employees can have same names, addresses, phone numbers but cannot have the same ID.
Answer:
I'm guessing C
Explanation:
It just makes the most sense to me, but please don't be really confident with it, I'm in 6th grade. I'm really sorry if I'm incorrect.
13? 13 is most minimum ages however, I don't understand this question all that well.
MAC address
....................
