In To Kill a Mockingbird, what are some examples in which fear and racism overpowered reason and intelligence?

BOB
EWELL'S ACCUSATION.  The most
obvious example comes when Bob Ewell accuses Tom Robinson of raping his daughter,
Mayella. Bob's hatred of Negroes is even greater than his dislike of nearly everyone
else.

THE
LYNCH PARTY.  The otherwise
upright citizens who attempted to get past Atticus at the jail allowed their fear of Tom
to override their good senses. Luckily, Scout's words of wisdom brought them back to
reality.

BOB
EWELL STALKS.  Tom's death
wasn't enough for Bob. He felt the impulse to stalk and frighten Tom's wife, Helen, as
well.

DOLPHUS
RAYMOND.  Raymond's decision to spend his wife with
Maycomb's Negroes makes the rest of Maycomb's white community think he is mentally
unstable and/or a drunk.

Why is the marginal propensity to consume and the marginal propensity to save always equal to one?

Any increase in the disposable income is apportioned by
individuals and households for two purposes. Part of the additional income is used for
increasing expenses, and the rest is used for increasing the saving. At any point of
total disposable income, the sum of total saving plus total expenses of an individual is
exactly equal to the disposable income. Also any increase in disposable income is
exactly equal to sum of corresponding increases in expenditure and
saving.

The marginal propensity to consume and save are
defined as:

Marginal propensity to
consume

= (Marginal increase in consumption)/(Marginal
increase in consumption)

And Marginal propensity to
save

= (Marginal increase in saving)/(Marginal increase in
consumption)

Therefore sum of marginal propensity to
consume and marginal propensity to save is:

= [(marginal
increase in expenditure) + (Marginal increase in saving)]/(Marginal increase in
consumption)

= (Marginal increase in consumption)/(Marginal
increase in consumption)

=
1

Thus sum of marginal propensity to consume and marginal
propensity to save is always equal to 1.

In Act II please identify and explain an example of dramatic irony.

In addition to the other answers, consider the tension created in the first two scenes.  In Scene 1, the witches gather to discuss what a rotten piece of work Macbeth is:

First Witch: ‘When shall we meet again,
In Thunder, lightning, or in rain?
Where the place?’
Second Witch: ‘Upon the heath.’
Third Witch: ‘There to meet with Macbeth.’
All: ‘Fair is foul and foul is fair
Hover through the fog and filthy air.’

The audience, therefore, already has an opinion of Mabeth before the man is even seen on stage.

In Scene 2, however, we hear the soliders and nobles discussing what a swell guy their leader is. 

King Duncan: O valiant cousin! Worthy gentleman!
Sergeant: I must report they (Macbeth and Banquo, another soldier) were as cannons overcharged with double cracks, so they doubly redoubled strokes upon the foe.

Dramatic irony is created in the tension between the two portraits.  Is Macbeth a hero or a villian? 

What were the characteristics of the communist takeover in Eastern Europe?

The first characteristic, in most Eastern Bloc countries,
was the violent nature of the takeover.  After being overrun by German armies, the
countries were again overrun by their liberating comrades in the Russian army.  A
relatively immediate and forceful government takeover of nearly all aspects of life
followed.  Remember that this is not just socialism, it is communism, so the government
controls not just the means of production, factories, farms, etc., they also control any
product coming out of those producing enterprises as
well.

The state quickly became an overwhelming force in
people's lives.  Religion was not allowed in many of the Eastern Bloc countries, travel
and freedoms of most kinds were restricted, and social mobility was reduced even
further.  There were pogroms in many Eastern European countries where those whom Stalin
saw as being possible resistors to his agenda were killed by the
millions.

Some countries were not quite as severely
restricted, Yugoslavia was one, but in general, most of the Eastern Bloc disappeared
behind the Iron Curtain.

What is international trade?

International trade is when goods are sold by firms or
governments in one country to customers in another country.  International trade is very
important to the economies of almost every country in the world.  It is also very
controversial.

For example, many goods bought in the US are
made in China.  Many people are unhappy about this because they feel trade takes jobs
away from Americans and gives them to Chinese.

Economists,
however, believe that trade is good for all countries involved.  They say it allows
people in all countries to get more goods for lower prices than they otherwise
would.

Why does the ghost reappear in Act 3, Scene 4?

The reappearance of the ghost has symbolic significance beyond simply spurring Hamlet on to revenge or clearing Gertrude of any wrongdoing.  It seems that Shakespeare wishes to associate the depth of his characters’ sensibilities and levels of awareness to their relative sensory experiences of the ghost.  For example, the sentries are able to see the ghost but neither hear him nor speak to him.  They, as a whole, are aware that something is rotten in the state of Denmark, although they cannot quite deduce the cause of the disintegration.  Hamlet, on the other hand, is not only able to see the ghost but he is also able to hear the ghost’s words and speak to him.  Hamlet is, of course, fully aware of how rotten the State of Denmark is, as well as of the cause of its disease.  The reappearance of the ghost in Act 3, Scene 4, therefore, guides the audience to a more favorable interpretation of the naive Gertrude. Shakespeare intends the audience to regard her as a wholly innocent victim, oblivious to the gambits of her current husband and unaware of the depths of both Hamlet’s psyche and mandate. This interpretation allows the audience to regard Claudius as the true antagonist of the play instead of mistakenly believing Gertrude might serve in this capacity, a grave misinterpretation committed by even some renowned scholars such as T. S. Eliot.

How does Huck use irony in the discussion between Huck and Mrs. Phelps about alleged steamboat accident?

Huck pretends to be someone else and tells a fabricated
story about why his steamboat took so long to reach its destination. He explains a
cylinder blew up, causing the delay. Mrs. Phelps wants to know if anyone was hurt. Huck
explains that no one was hurt and then goes on to say that a black person was killed.
Mrs. Phelps is happy to hear this because she knows having a cylinder explode can be
very dangerous.

The fact that Mrs. Phelps does not view the
death of an African-American as a tragedy is ironic, because we as readers view it as a
loss of human life while Mrs. Phelps does not.