Question

why are few new hydroelectric dams being built in the u.s.? large dams can disrupt ecosystems. wind energy has replaced all dam functions. water is not readily available. solar energy systems are cheaper to build.

Explanation:

• For the option "Large dams can disrupt ecosystems": Building large hydroelectric dams can cause significant disruption to local ecosystems, such as altering river flows, affecting fish migration, and changing habitats. This environmental concern is a major reason why few new hydroelectric dams are being built in the U.S.
• For "Wind energy has replaced all dam functions": Wind energy has not replaced all dam functions. Dams have other purposes like flood control, water storage, etc., in addition to power generation, so this is incorrect.
• For "Water is not readily available": The U.S. has many water sources, and lack of water availability is not the primary reason for not building new hydroelectric dams.
• For "Solar energy systems are cheaper to build": While solar energy is a growing sector, the cost of building solar systems being cheaper is not the main reason for the lack of new hydroelectric dams. The environmental impact of dams is a more significant factor.

Answer:

A. Large dams can disrupt ecosystems.