HELP please i need one of seven key concepts for - From the Book of Local Miracles, Largely Unrecorded (187-188)

Which tone best fits a business letter

Which detail from the text best demonstrates the effect of totalitarianism on the animals? "progress was made in the dry frosty weather that followed." "it had been decided to build the walls three feet thick." "they were always cold, and usually hungry as well." "for a long time the quarry was full of snowdrifts and nothing could be done."

What is a mechanism by which organisms maintain homeostasis when the level of one substance influences the level of another substance or the activity of an organ.