Answer:
Hydraulic engineering is just a part of civil engineering. It is based on flow and conveyance of fluids, mainly water and sewage. It can be seen as an application of fluid mechanics for taking care of problems arising during storage, transport, regulation, measurement and use of water. This is needed while designing dams, canals, or cooling water facilities for thermal power plants.
The Prime Meridian marks zero degrees longitude. Without it, the other degrees of longitude cannot be measured.
C) mountains
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