Oil and vinegar is used for preservation for
(a)Vegetables
(b)Fish
(c)Meat
(d)All of the above

Hint: Vinegar is a 5%-10% aqueous solution of acetic acid which is used for food preservation as well as adding flavor to food. Oil and vinegar are used in food preservation because food spoilage microorganisms cannot survive in such an environment.

Complete Answer:
Oil and vinegar are used for the preservation of vegetables, fish, and meat. Immersion of food in vinegar to preserve it is known as pickling. The primary causes of spoilage of food are microorganisms like bacteria, yeast, or molds which shorten the lifespan of the food. Some harmful pathogens might also be present in the food which can cause diseases if eaten. The acidic environment of vinegar and anaerobic environment of oil prevents the further growth of microorganisms thus increasing the shelf life of food.

Additional information:
Let us look at some more ways by which we can preserve food.
Refrigeration: Cold temperatures inhibit the growth of microorganisms by pausing their metabolism and thus keeping food in cold temperatures by refrigeration is a great method to preserve food.
Preservation by salt: Common salt prevents the growth of microorganisms by removing moisture from the cells of such organisms. It is used to preserve meat and fish for ages.
Preservation by sugar: Sugar is used as it also removes the moisture content and is used in foods like jams, jellies, and squashes.
Pasteurization: This method was invented by the French scientist Louis Pasteur who also gave the famous swan-neck experiment. In this process liquids like milk and juice are heated to 700 C for 15 to 30 seconds and then suddenly chilled. This prevents the growth of any harmful bacteria.

So, the correct option is ‘All of the above’.

Note:
-Boiling liquid food can also be a method of food preservation as microorganisms are completely killed by heat.
-Chemicals that are used for food preservatives like oil, vinegar, salt, and sugar are known as preservatives.
-Sodium benzoate and sodium metabisulphite are also some common preservatives.