A paragraph is a group of sentences written to develop one MAIN IDEA about a given TOPIC and DETAILS that support the main idea. The ability to recognize the topic, main idea, and details helps the reader to understand the information contained in each paragraph of a text.
 

TOPIC	The topic is the subject the writer is writing about. It is usually expressed in very few words. To identify the topic ask yourself the following question:  "What is this paragraph (or text) about?"
MAIN IDEA	The main idea is the primary point the writer makes about the topic. The main idea is supported by the details in the paragraph. To identify the main idea ask yourself this question: "What is the author saying about the topic?" A main idea can be stated or implied. Stated: A complete sentence (TOPIC SENTENCE) written in the paragraph tells the central point of the paragraph and is supported by the details in the paragraph. LOCATION of the TOPIC SENTENCE: Very often it is the first sentence in the paragraph. However, it can also be in the middle as well as at the very end of the paragraph. Implied: The main idea is not written in the paragraph. You have to read the paragraph, analyze the details and determine what idea they are supporting.
DETAILS	To prove or explain the main idea, the writer uses supporting details that can take the form of facts, examples, events, reasons or comparisons. MAJOR DETAILS contribute directly to the main idea. MINOR DETAILS usually elaborate on some major detail that supports the main idea. To identify the major details ask yourself the following question: "What major details or evidence does the writer use to support the main idea?"

Paragraph unity

A paragraph must be unified. The word “unified” begins with the prefix uni- meaning one; therefore, your paragraph must contain one main-idea sentence and supporting details that discuss one point of view.  We have unity in a paragraph when everything in the paragraph relates to the main idea introduced in the topic sentence.

Paragraph Coherence

There should be a logical relationship or connection between all the ideas in the paragraph.

A paragraph can be compared to an ordinary sandwich. The main-idea sentence (topic sentence with the controlling idea) and the concluding sentence have the same functions as the two pieces of bread; they must hold the paragraph together. The supporting details, on the other hand, are the filling; they should be substantial enough to create a complete and satisfying “meal” for your reader. Study the following example:

Read the following paragraphs and answer the questions below.
 

I. After food is ingested, digestion in different parts of an alimentary tract is achieved by mechanical and chemical means. Mechanical digestion carried out, for example, through muscular grinding by teeth and stomach, achieves a progressive physical subdivision of ingested materials into fine particles suspended in water. Chemical digestion then reduces these particles to molecular dimensions. In the process, usable ions and molecules become separated out, and more complex molecules are broken up into smaller, usable ones.

1. What is the topic of the paragraph?

a) the alimentary tract
b) the human body
c) digestion

2. What is the main idea of the paragraph?

a) digestion is achieved by mechanical and chemical means
b) digestion takes place in different parts of the alimentary tract
c) muscular grinding by teeth and stomach are an important part of the digestion

3. What are the two major supporting details of the paragraph?

a)  ______________________________________________________________________________________
 

b)  ______________________________________________________________________________________
 
 
 

II. Astronomers have long seen our sun as sort of average size among stars. But lately it seems very small, thanks to the discovery of the Pistol Star. Detected near the center of our galaxy by the Hubble Space Telescope’s new infrared camera, and named after the gun-shaped nebula that surrounds it, the Pistol is roughly a hundred times as massive as the sun and anywhere from 2,5 million to 15 million times as bright. If it were not veiled by dust, it would be visible to the naked eye, even though it is 25,000 light-years away. If it were placed in the center of our solar system, its surface would extend to Venus. The Pistol Star may be the brightest, most massive star ever seen.

1. What is the topic of the paragraph?

a) the Hubble Space Telescope
b) the size of the sun
c) the Pistol Star
 

2. What is the main idea of the paragraph?

a) The sun seems very small, thanks to the discovery of the Pistol Star.
b) The Pistol Star may be the brightest most massive star ever seen.
c) The Hubble Space Telescope’s new infrared camera discovered a new star.

3. What are the three major supporting details of the paragraph?

a)  ______________________________________________________________________________________

b)  ______________________________________________________________________________________

c)  ______________________________________________________________________________________
 
 
 

III. Physically, caffeine speeds up the heart, promotes the release of stomach acid, and increases urine production. It also dilates some blood vessels while narrowing others. In large amounts, caffeine may cause convulsions, but this is not too likely. It takes about ten grams of caffeine, about 100 cups of coffee, to run a serious risk of death. Psychologically, caffeine suppresses fatigue or drowsiness and increases feelings of alertness. Caffeine then can have various effects on a person.

1. What Is the topic of the paragraph?

________________________________________________________________________________________

2. What is the main idea of the paragraph?

________________________________________________________________________________________

3. What are the two major supporting details of the paragraph?

a)  ______________________________________________________________________________________
 

b)  ______________________________________________________________________________________
 
 
 

IV. Dangerous levels of mercury are threatening the world’s largest wetland, the Panatal in southwestern Brazil. The mercury is dumped into the river that flows into the Panatal by goldminers who use it to extract the precious metal from silt. Researchers say fish have been found contaminated 24 times the level of mercury the World Health Organization considers safe. The Panatal has one of the world’s largest concentrations of wildlife. Mercury poisoning is upsetting the whole ecosystem. Some people in the Amazon basin are also suffering from the effects of mercury poisoning.

Write the letters that correspond to the sentences that constitute the MAIN IDEA and two MAJOR SUPPORTING DETAILS of the paragraph.

a) Dangerous levels of mercury have been detected in the Panatal.
b) The Panatal is threatened by dangerous levels of mercury.
c) Goldminers have dumped mercury into the river that flows into the Panatal.
d) Fish have been found contaminated 24 times the level of mercury the World Health Organization considers safe.
e) The Panatal has one of the world’s largest concentrations of wildlife.
f) Mercury poisoning is upsetting the whole ecosystem.
g) Some people in the Amazon basin are suffering from the effects of mercury poisoning.
 

MAIN IDEA              ____
MAJOR DETAIL 1    ____
MAJOR DETAIL 2    ____
 
 

V. What causes cancer? The basic causes are unknown, although certain conditions that may lead to cancer have been identified. For example, we know that repeated injury to the cells is a factor. Such damage may result from overexposure to the sun, excessive radiation, and contact with certain chemicals. We also know that some forms of cancer in animals have been caused by viruses. Most physicians and scientists who have studied the problem believe that cigarette smoking is the principal cause of lung cancer. Nevertheless, because of our limited knowledge of what precisely causes cancer, research to find the basic causes of human cancer is still under way in many fields of science.

1. What is the topic of the paragraph?

________________________________________________________________________________________

2. What is the main idea of the paragraph?

________________________________________________________________________________________
 

3. What are the three major supporting details of the paragraph?

a)  ______________________________________________________________________________________

b)  ______________________________________________________________________________________

c)  ______________________________________________________________________________________
 
 
   

VI. Three of the five patients using permanent artificial implants are now dead; the other two are confined to the hospital after suffering strokes and other complications. The strokes, which have struck at least four patients, appear to be caused by blood clots generated by the Jarvik 7 artificial heart, the most widely used device. Various patients have also suffered internal bleeding, respiratory problems, suppression of the immune system and recurrent infections.

1. What is the topic of the paragraph?

________________________________________________________________________________________
 

2. What is the main idea of the paragraph?

______________________________________________________________________________________