General vs specific for article

The is not used when we refer to nouns used in a general or universal sense.

Example:
1. Rice is grown in many countries.
2. Gold is an expensive commodity.
3. Oranges are sold in the market.
4. Man is a rational creature.

But “the” is used if we referring to a particular kind.

1. The rice we eat is exported from many countries.
2. The gold sold at that jeweller’s is of a high quality.
3. The oranges we eat every day are bought from the market.
4. The man standing at the corner of the street is looking at you.