How can volcanoes and rivers be both constructive and destructive forces

Volcanoes can be constructive if they happen in the ocean, as they can form islands and therefore be new places for plants and animals to grow and thrive.

Volcanoes can be destructive if they kill a large amount of animals by forming on land.

Hope this helps :)

evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.