Which trend is observed as the first four elements.

What is the missing step in this proof? scroll down to see the entire proof. u

Based on the narrator's comments about living with the widow douglas, the reader can infer that a) the narrator doesn't care much for civilization and its strict rules. b) the narrator admires and wants to become more civilized and refined. c) the narrator is extremely religious and of high moral standing. d) the narrator desires to become a productive member of society.

Summarize the work of famous environmental scientists of the past.