Dam is a wall across a river.

Dam is a wall across a river.

• A. A bridge across a river
• B. A source of water
• C. A river
• D. A wall across a river

Answer: (D)

A dam is built to block and control the flow of water in a river, acting as a barrier. So describing it as a wall across a river fits perfectly, since the dam’s job is to hold back water and create a reservoir. The other options describe something different: a bridge is for crossing the river, a source of water is where water comes from, and a river is the moving water itself.

A dam is built to block and control the flow of water in a river, acting as a barrier. So describing it as a wall across a river fits perfectly, since the dam’s job is to hold back water and create a reservoir. The other options describe something different: a bridge is for crossing the river, a source of water is where water comes from, and a river is the moving water itself.