Answer:
Find the explanation below.
Step-by-step explanation:
Sentence A: In sentence A, the bolded words create a positive undertone to the entire meaning of the text. Words such as unimaginable accomplishment, stunning, and fascinated produce a pleasing and heartening mood. They make it clearer to the reader that this action by the scientists elicited a favorable response from the viewers.
Sentence B: In sentence B, there is a negative undertone to the text. The use of descriptors such as shocking, recklessly, alarmed, tells the reader of the unfavorable response the action of the scientists produced in the viewers. A gloomy mood is thus created.