How do muscles produce mechanical energy?

Your body takes in chemical energy in the form of food, drink, etc. As your body breaks down what you put in, chemical energy is stored in the muscles. Muscles transform the chemical energy into mechanical when they contract. Oxidation of fats and carbohydrates and anaerobic chemical reactions are both used to move muscles. These chemical reactions produce ATP. Muscles use ATP to move the myosin heads "against" actin which causes the muscle to contract.

Why is the bacterium Pseudomonas so dangerous?

Pseudomonas aeruginosa is a virulent bacteria, because of it's secreted toxic components, substances that have the ability to destroy tissues and blood cells. The good news is that the bacterium is an opportunist, that means that it causes infections only under certain conditions: e.g. in the context of other infections, when the body is already weak, in  infants with congenital anomalies, dystrophic children, people with cystic fibrosis who are more susceptible to infections, etc.. So, in conclusion, it infects people who have a weak immune defense.

The bacterium is so dangerous because it is resistant to many antibiotics: e.g. penicillin and others. It has high resistance to antibiotics because it contains in it's structure, more accurate in it's the membrane, some proteins that eliminate antibiotics to the outside as they entered inside the bacteria, before they manage to destroy it. This is a natural antibiotic resistance but the resistance could be also acquired, because of the unjustified use of antibiotics.

Who are characters and what are their motivations behind their actions in the play ?

Thomas Putnam-This is a man who feels he is entitled to more than he has gotten. His long history with the community gives him this idea, and he is resentful that his brother-in-law was not appointed minister. Putnam uses the hysteria to build his land holdings. He has his daughter accuse people in  court, and then profits from the accused need to sell their land cheap.

Mary Warren- is a servant in the Proctor home and a part of Abigail's group. She feels a sense of pride at her part in the court proceedings and uses this as leverage in the Proctor house. She is weak, however, and is tugged between Proctor's demands and Abigail's threats.

John Proctor - is a man who is in need of redemption. After a disastrous affair with Abigail, he has lost his integrity. By refusing to participate in the finger-pointing, and then refusing to lie to save his life, he regains his good name. 

In act 1, scene 5 of Hamlet, what does the character Hamlet mean by "wings as swift as meditation"?

Hamlet describes this dialogue where in he uses simile and metaphor and urges the ghost to be swift, when the ghost is going to disclose the secret of his father’s murder. In it, wings are used. It is symbolized for bird and he wishes to reach the murderer quickly before thought or meditation in order to take revenge.
As that hamlet is a noble prince and possesses quite discriminated qualities, he is afraid of his tendency to love or his thought of love may extinguish his feelings of revenge:
Haste me to know`t that I with wings as swift
As meditation or the thought of love
My sweep to my revenge.
He wants to perform his job speedily as that love or any thought may not interfere. It will bring resistance between me and my revenge.

How does Shelley return to her frame story in chapter 24?

The remainder of the book is again written in letters to his sister Margaret in Enlgland.  This is where he tells of Victor's decline in health, the mutiny of his own sailors, and the visit of the creature after Victor finally passes.  He records in letters the creature's conversation and also his vow to kill himself.  He says that Robert is the last of his kind to see the monster with his own eyes, that the creature will build a funeral pyre and lavish in the torture of the flames.  So, he does not kill himself in the novel...it happens after the book has ended, but the creature has always been a "man" of his word.

The novel begins and ends with Robert Walton writing letters to his sister.

In the story "The Lesson," what is the lesson that Miss Moore is trying to teach the children?

Miss Moore wants to teach the children that there is "more" in life that what their ghetto neighborhood offers.  In showing them there is "more," she hopes they will reach for "more." However, when the narrator says at the end "There ain't nobody gonna beat me at nuthin," we are not sure if she has learned the lesson or not for throughout their trip to the city she resists what Miss Moore has to say because she doesn't want to appear stupid--she wants to be a tough know-it-all.  Miss Moore is concerned that such an attitude might limit the child rather than expand her possibilities in life.

In To Kill a Mockingbird, what does Lee show about Atticus' character when Scout asks him the meaning of the term "n****r lover"?

It reveals that Atticus is above the accepted social codes of Maycomb.  There now have been several instances where Atticus has been references like this.  Scout beat Cecil Jacobs up for a similar references.  Scout lets Francis have it at Christmas time when Francis called Atticus that (no doubt hearing it from Aunt Alexandra).  And now Miss Dubose adds to it.

Maycomb is deeply racist and set in those racist ways, so they feel Atticus should do very little to help Tom.  Furthermore, even attempting to help him is seen as unimaginable.  Yet, Atticus doesn't accept those beliefs.

All their lives Atticus has told the children to have empathy and compassion.  How could he not accept this burden?  This is scene when he explains to Scout that "N-lover is just one of those terms that don't mean anything -- like snot nose.  It's hard to explain -- ignorant trashy people use it when they think somebody's favoring Negroes over and above themselves" (108).  This is keeping in line with Atticus's ability to empathize with others.  He most certainly is putting Tom's welfare over his own.  Just look at the repercussions that affect Atticus and his family after the trial.