Which best states the central idea of this excerpt? it is always necessary to work with a partner when dealing with unidentified substances. extreme precautions must be taken when dealing with potentially hazardous materials. scientists are well known for being overly cautious and for taking unnecessary safety measures. it is standard procedure to wear both space suits and hearing protectors in laboratories.

Question: Which best states the central idea of this excerpt? it is always necessary to work with a partner when dealing with unidentified substances. extreme precautions must be taken when dealing with potentially hazardous materials. scientists are well known for being overly cautious and for taking unnecessary safety measures. it is standard procedure to wear both space suits and hearing protectors in laboratories.

The central idea of the excerpt is that extreme precautions must be taken when dealing with potentially hazardous materials. The excerpt states that "unidentified substances should always be handled with extreme caution," and that "all personnel must wear full protective gear when working with potentially hazardous materials." This emphasizes the importance of safety when dealing with unknown or potentially dangerous substances.

The other answer choices are either incorrect or irrelevant to the central idea of the excerpt.

Answer choice A is incorrect because it is not necessary to always work with a partner when dealing with unidentified substances. In some cases, it may be safe to handle an unidentified substance alone, if the proper precautions are taken.
Answer choice B is irrelevant to the central idea of the excerpt. The excerpt does not mention the caution of scientists or the standard procedures in laboratories.
Answer choice D is incorrect because it is not standard procedure to wear both space suits and hearing protectors in laboratories. Space suits are typically only worn in outer space, and hearing protectors are only worn in noisy environments.

Overall, the central idea of the excerpt is that extreme precautions must be taken when dealing with potentially hazardous materials. This is important to remember in order to protect yourself and others from harm.