What are three reasons why the animals listen to Old Major in Orwell's Animal Farm?

I am sorry that I had to pare down your question.  I would
advise you to repost them so that you can get guidance for your
exam.

The animals listen to Old Major's speech for a
variety of reasons.  The most fundamental of which is that Old Major's vision is a way
for the animals to reconfigure the role they play in their world.  Old Major is very
pointed in how the animals are exploited by the humans such as Mr. Jones.  For example,
Old Major makes a pointed case that Boxer will be sent to the knacker when he is no
longer of use. Old Major's vision is one where the animals are able to make sense of
their suffering and be able to understand why they are in the position in which they are
immersed.  Another reason why the animals listen to Old Major is that he is seen as a
figure of respect.  Old Major's age and stature is one whereby he is perceived as one
who has seen a great deal of life on the farm, so that his insights are meaningful to
the animals. Another reason why the animals listen to Old Major is because he gives them
not only the cause of why they are suffering, but a solution to their problems.  His
solution is that if the animals assert control of their own lives and of their own
existence in owning the means of production on the farm, they will no longer be
enslaved.  This is a hopeful vision of the future, one in which the animals feel a
certain level of redemption out of their present predicament of suffering.  It is for
these reasons that the animals listen to Old Major in the henhouse.  He introduces the
vocabulary of revolution to the animals, the catalyst for
change.