Final answer:
The italicized pronoun 'These' in the sentence is a demonstrative pronoun, which is used to point directly at something that is likely close to the speaker.
Step-by-step explanation:
The italicized pronoun in the sentence 'These are truly amazing discoveries' is 'These'. It belongs to the class of demonstrative pronouns. Demonstrative pronouns, such as 'this', 'that', 'these', and 'those', are used to point directly at something.
They essentially act like pointers in language, clarifying which object or objects are being referred to in relation to their distance or position from the speaker. In this context, 'these' is referring to some discoveries that are likely close to the speaker, either physically or figuratively.