The answer is D.
"Keep", "factor", and "calculate" are all verbs in the list of things the new system allows teachers to do. The other sentences are inconsistent with their list of verbs/adjectives/nouns. Thus, option D is the only one that is grammatically correct.
I am not too good at explaining, so let me know if you are still confused.
Hope this helps! :)
In my opinion, no. If it was okay, the human population wouldn’t be so big for one. Also it’s not right. Yes people will test the limits, but that doesn’t give someone the right to end another’s life for it.
B) because sectioning them is easier to read and see and helps maintain order throughout the presentation of the article. Hope I helped! :)
~ Destiny ^_^
Goldfish will move differently depending on the tempature of water