Why are supermarkets called self service stores

Early self-service grocery stores did not sell fresh meats or produce. Combination stores that sold perishable items were developed in the 1920s. ... They defined the attributes of a supermarket as "self-service, separate product departments, discount pricing, marketing and volume selling".

It is said so because customers pick their desired products up all by themselves and pay on the counter

Explanation:

b) trade is easy because of the direct line between their major ports. bilateral trade reached 89,6 thousand million.

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