B because it is the only reasonable amount of times you could do. The other answers are way to long or way to short.
These are all true exact for these last one; forming acidic oxides is not a property of metals
Primary sources, for example, are witnesses. If there was a witness to a murder, they would be considered a primary source because they can give the police a first hand view of what happened. Published research, newspaper articles, and other media would be secondary sources as they are not at the event but just commentating and/or making observation from what they can tell from videos and gossip. Let me know if you have any more questions.
The answer is their books to class answer c
According to ( https://www.espressoenglish.net/100-common-english-adverbs/ ) I belive it's "up'' and "so"
