In a sentence using active voice, the subject of the sentence performs the action expressed in the verb. In an active sentence there is only one verb.
The answer is A! I hope you get it right!
Based on the scenario above, Cliff can be described as
someone who is having a high comparison level and also, a low comparison level
for alternatives. The comparison level is where it is being referred to the
relationship expectations that an individual has experienced on his or her
past.
Answer:
The development of antibiotics and immunizations.
Explanation: