If the sentence in question is a statement (ends with a period), I would probably "however" as your transition word.
Answer:
We can learn a lot, we can know how other people had struggled and suffered during those times. It tells us that it is very truamatic and how sad and miserable it was. It would tell us if there was another crisis, we need to stop it immediently so we would avoid getting people killed. The hlocaust was very depressing and many lives were lost and this makes us all sympathetic.
Explanation:
C) Biologists backed up these ideas with sketches and models based on known animals.
The answer is: adverb.
The phrasal verb bring forth consists of a verb an an adverb. It means to produce or generate.
A phrasal verb is the connection of a verb plus an adverb, preposition or both. Its meaning depends on the adverb or preposition that follows the verb. Furthermore, a single phrasal verb usually has more than one meaning.