Refer(s) primarily to what people do in a religious community, whereas refers to the human need for a deeper meaning. a. spirituality; religion b. religion; religion c. religion; spirituality d. religious behaviors; religion

I believe the answer is: Religion; spirituality
Spirituality usually arises as humans make effort to obtain deeper understanding of themselves as an individual and our relation to the universe in general. Religion is the medium that people use as a basis for the spiritual journey

It was mostly "b. Food shortages" that was an immediate cause of the 1917 revolution in Russia, since the monarchy in Russia before this time was highly extractive.