could you okease explainme the answer pf these questions 1 , 2 and 3

please

if were possible to explain me

thanks

Q1: What is a primary key? Define with an example. Q2. Look at the sample table (CUSTOMER) below and identify the column most appropriate to be the primary key. (If there is no appropriate primary key you can add a column which will act like a primary key.) Q3: Look at the sample table (PET) below and identify the column that is most appropriate to be the primary key. (If there is no appropriate primary key you can add a column which will act like a primary key.)