Is a negative feed back loop limited to one effector

Which of the following citations correctly follows mla guidelines? a. tanya somanader. "we are stronger because we aredemocracies': president obama addresses the people ofestonia." the white house blog 3 sept. 2014. print. 4 sept. 2014.b. "we are stronger because we are democracies': presidentobama addresses the people of estonia" by tanya somanader. the white house blog 3 sept. 2014. web. 4 sept. 2014.c. somanader, tanya. "we are stronger because we aredemocracies': president obama addresses the people ofestonia." the white house blog 3 sept. 2014. web. 4 sept. 2014d. somanader, tanya. the white house blog. "we are strongbecause we are democracies: president obama addresses thepeople of estonia." 3 sept. 2014. web. 4 sept. 2014.

The excerpt is from a longer essay on huckleberry finn by mark twain. what kind of support is used to develop the writer's main idea regarding how twain brought his characters to life?

Why are reading and writing necessary in today’s world?