Iron rusts when it comes in contact with water because of

Layer of aluminium oxide.

D. china is one of the most active places, which could quite possibly mean more agriculture will happen.. and more war machi-    best of luck comrade.

Essential for a scientist to do for credibility

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.