Runway threshold is indicated by a series of parallel lines starting from a distance of________?

Center of gravity of a solid cone lies on the axis at the height________?

If the width of the foundation for two equal columns is restricted, the shape of the footing generally adopted, is________?

The drainage water intercepting the canal can be disposed of by passing the canal below the drainage in________?

Pick up the correct statement from the following?

A pre-stressed concrete member is preferred because________?