Answer:
- gradually stopped responding to the tone.
Explanation:
According to Pavlov's theory of 'Classical Conditioning,' the dog's conditioned response of salivating on hearing the tone of a metronome will decrease and eventually disappear if he continues to offer the tone without giving food. This shows that the conditioned response will reappear for a short-period only if the conditioned stimulus returns. He also displayed that after a specific rest period, the extinct conditioned response reappears which he called 'spontaneous recovery of conditioned response.'
It's the third sentence "They spotted many interesting shops heading up the escalator. "
In my opinion, the correct answer is <span>B: "He asked himself where it had come from and how; the past provided no explanation, and the future could not justify it." This is the only instance when the main character tries to discover the source or roots of his happiness and infers that it hasn't resulted from any action from the past, nor from anything that might yet happen. The other options present this happiness as something that is almost a burden to him, and that's why they are examples of dark humor.</span>
Romeo had been in his room crying.
Hope this helps!