The central idea of this excerpt is that Utopians make a regular effort to care for those in need.
Which detail best supports this central idea?
A council is held every year in Amaurot.
Three people from each town are sent to the council.
The council examines the surrounding towns.
Towns with an abundance provide for those with less.

Towns with an abundance provide for those with less.

Explanation:

In the great council at Amaurot, to which there are three sent from every town once a year, they examine what towns that are rich and those who do not have enough so that the rich towns can help those with less. This is done freely by the towns without no any form of payment either now or in the later future. According to the abundance or scarcity at any of the towns, they supply or are supplied from one another, so that indeed the whole island is, as it were, one family.

it is the nurture that decides the behavior of a child.

explanation:

naturally, children are pure. it is an environment and the type of attention a child gets that determines their behavior.  

i believe the answer is: b. mr. head had a long, tube-like face with a rounded open jaw and a short depressed nose.

this is because in the un-revised sentence it said that mr. heads face was long and tube-like, and he had a rounded open jaw. this is not a very grammatically correct because of how it seems to drag on with the and, replaced with, with, makes it sound more fluent in the description.