There are two types of cells. Prokaryotic cells do not have a clear and easy-to-see nucleus, and do not have a membrane, or wall, around them. Eukaryotic cells have an easy-to-see nucleus where all of the cell's functions take place, and a membrane around them. The main organelles of a cell and their uses are:
Christian
A Christian () is a person who believes in Christianity, a monotheistic religion. Christianity is mostly about the life and teachings of Jesus Christ, in the New Testament and interpreted of prophesied in the Hebrew Bible/Old Testament. Christianity is the world's largest religion, with 2.1 billion followers around the world.
Christians consider the Holy Bible to be a sacred book, inspired by God. The Holy Bible is a combination of the Hebrew Bible, or Torah, and a collection of writings called the New Testament. Views on the importance of these writings vary. Some Christian groups prefer to favor the New Testament, while others believe the entire Bible is equally important. Also, while many Christians prefer to consider the Bible as fully true, not all Christian groups believe that it is completely accurate.
The question of "Who is a Christian?" can be very difficult. Christians often disagree over this due to their differences in opinion on spiritual matters. In countries where most persons were baptized in the state church or the majority Christian church, the term "Christian" is a default label for citizenship or for "people like us".
In this context, religious or ethnic minorities can use "Christians" or "you Christians" as a term for majority members of society who do not belong to their group - even in a very secular (though formerly Christian) society.
Persons who are more devoted the their Christian faith prefer not to use the word so broadly, but only use it to refer to those who are active in their Christian religion and really believe the teachings of Jesus and their church. In some Christian movements (especially Fundamentalism and Evangelicalism), to be a born-again Christian is to undergo a "spiritual rebirth" by believing in the Bible's teachings about Jesus and choosing to follow him.
Many Christians choose to go to church. Most Christians believe this to be a sign of their religious devotion to God and an act of worship. However, some Christian groups think that one can be a Christian without ever going to a church. Though there are many different viewpoints on the issue, most Protestants believe all Christians are part of the spiritual church of Christ, whether or not those Christians go to an actual church each week. On the other hand, Catholics in the past have believed that the Holy Catholic Church is the only true church.
Cheese
Cheese is a dairy product that is made from milk. There are many types of cheese, such as cheddar, Swiss, and provolone.
Many things affect the form, texture, colour and flavour of a cheese. These include the milk (cow or goat), if the milk has been pasteurized, the amount of butterfat, bacteria and mold in the cheese, how the cheese is made, how much fat is in the cheese, and how old the cheese is. Example for cheese used in a sentence: Todd the dog likes cheese.
People have been making cheese since before history was written down. It is not known when cheese was first made. It is known that cheese was eaten by the Sumerians in about 4000 BC.
Cheese is made using milk. The milk of cows, goats, and sheep are most popular. Buffalo, camel, donkey and even hippopotamus milk can also be used. Cheese makers usually cook the milk in large pots.
Most cheeses are acidified by bacteria. This bacteria turns milk sugars (such as lactose) into lactic acid.
Salt is added, and a substance from the stomach of young cows called rennet. This curdles the cheese and makes it solid. Some makers do not add rennet, but curdle the cheese in other ways. Vegetarian alternatives to rennet are made by fermentation of a fungus called "Mucor miehei". Other alternatives use species of the "Cynara" thistle family.
Other ingredients are added and the cheese is usually aged for a varied length of time.
There are many different ways to classify cheeses. Some ways include:
There are also man-made foods that some people use instead of cheese. These are called Cheese analogues.
Different types of cheese include:
Constitution
The constitution of a country (or a state) is a special type of law document that tells how its government is supposed to work. It tells how the country's leaders are to be chosen and how long they get to stay in office, how new laws are made and old laws are to be changed or removed based on law, what kind of people are allowed to vote and what other rights they are guaranteed, and how the constitution can be changed.
Limits are put on the Government in how much power they have within the Constitution "(see Rule of Law )". On the other hand, countries with repressive or corrupt governments frequently do not stick to their constitutions, or have bad constitutions without giving freedom to citizens and others. This can be known as dictatorship or simply "bending the rules". A Constitution is often a way of uniting within a Federation.
The UK's constitution is not written in one single document like many other countries' are. In fact, the UK's constitution is not completely written down at all. Some of it can be found in writing, starting with the Magna Carta of 1215 and the Bill of Rights Act 1689 and including more modern Acts of Parliament. Other parts of it are considered common law and are made up of the decisions of judges over many hundreds of years in a system called legal or judicial precedence. Because of this, some people say that the United Kingdom has a "de facto" or "unwritten" constitution.
The United States in 1787 began a trend in the writing of constitutions. The United States Constitution is also the shortest that people are still using, and it has been changed (amended) many times over the years. It was made after the colonists won their independence from Britain. At first they had the Articles of Confederation but the Articles were replaced with today's Constitution.
The Indian constitution of 1950 is the longest ever written constitution in the world. It has 448 Articles and 12 Schedules in it, with 5 appendices and 98 amendments.
Circle
A circle is a round, two-dimensional shape. All points on the edge of the circle are at the same distance from the center.
The radius of a circle is a line from the centre of the circle to a point on the side. Mathematicians use the letter "r" for the length of a circle's radius. The centre of a circle is the point in the very middle. It is sometimes written as formula_1.
The diameter (meaning "all the way across") of a circle is a straight line that goes from one side to the opposite and right through the centre of the circle. Mathematicians use the letter "d" for the length of this line. The diameter of a circle is equal to twice its radius ("d" equals 2 times "r"):
The circumference (meaning "all the way around") of a circle is the line that goes around the centre of the circle. Mathematicians use the letter "C" for the length of this line.
The number "π" (written as the Greek letter "pi") is a very useful number. It is the length of the circumference divided by the length of the diameter ("π" equals "C" divided by "d"). As a fraction the number π is equal to about or 355/113 (which is closer) and as a number it is about 3.1415926535.
The area, "A", inside a circle is equal to the radius multiplied by itself, then multiplied by π ("A" equals π times "r" times "r").
π can be measured by drawing a large circle, then measuring its diameter ("d") and circumference ("C"). This is because the circumference of a circle is always π times its diameter.