Why are duplicate tuples not allowed in a relation?

Technician a says that a shop towel should never be used to clean around the flange area before replacing an automatic transmission filter. technician b says that a dimpled transmission fluid pan can be repaired. who is right

Brian wants to conduct an online search with a certain phrase. he intends to use the words books that belong to the 1800s in his search. how should he use the word that in his search?

Write a program that prints the day number of the year, given the date in the form month-day-year. for example, if the input is 1-1-2006, the day number is 1; if the input is 12-25-2006, the day number is 359. the program should check for a leap year. a year is a leap year if it is divisible by 4, but not divisible by 100. for example, 1992 and 2008 are divisible by 4, but not by 100. a year that is divisible by 100 is a leap year if it is also divisible by 400. for example, 1600 and 2000 are divisible by 400. however, 1800 is not a leap year because 1800 is not divisible by 400.