Answer:
C I think I'm so so sorry if I get it wrong
Answer:
I don't know the answer to this, but I know you would need to name something important, on this date.
Explanation:
I believe b, because then is considered a transition word
Deals with fears that are still relevant
16. penicillin
17. ecological
18. life story
19. health threat
20. life science
Hope this helped