B. Better managing our natural resources
The Harappa’s system of standardized weights and measures signified advance technology and an advancing civilization in the Indus River Valley. Remarkable accuracy in systems and tools of the Harappan people were demonstrated by fire-baked bricks which were consistently moisture resistant and uniformly sized.
The name for such a hole is "caldera" which is a word of Spanish origin meaning "a pot" or a "cooking pot" (thing of cauldron!) - and this word is used because it resembles the shape of this hole.
Often the Calderas are filled with water forming lakes and often there is an island in the middle of the water.
