Do you know why people look the way they look? What inside our bodies makes us grow in a certain way? The answer is DNA. It was first discovered by a young Swiss doctor in 1868.
DNA is like a computer program for your body. Almost every cell(细胞) in your body includes DNA. The way DNA in the cell decides why you are the way you are. For example your friend might have larger ears than you. This is because their DNA is different from yours.
DNA lives in the cell and is ordered in a structure called a “double helix(双螺旋)”. In each double helix there are links called as chromosomes(染色体). These chromosomes are made from four bases that arrange themselves in millions of different ways. The way these bases choose to line up is what makes the DNA code for that cell.
DNA is also called a “gene(基因)”. This is a very interesting thing. Genes are passed down from your parents. That is why you might have the same smile like your dad’s or mom’s!
In February, scientists found the skeleton(骨架) of Richard III, King of England from 1483-1485, under a car park in England. It seems unlikely that scientists could identify a 527-year-old skeleton. However, they matched the skeleton’s DNA to a sample from one of his direct descendants(后代). How amazing!
_______ discovered DNA.
A. A Swiss scientist               B. A Swiss doctor
C. A young student                 D. A Swiss worker
Which of the following is Wrong?
A. DNA is a part of the cell.
B. Different people have different DNA.
C. The chromosomes are made up of four bases.
D. Scientists could not identify a 527-year-old skeleton.
What is the main function of “genes”?

A．They decide your children’s appearances or characters.

B．They make your children have the same smile as you.

C．They make your children stay healthy.

D．They’re good for scientific researches.

What’s the main idea of this passage?
A. What decides DNA.             B. How DNA is arranged.
C. What genes are like.         D. How DNA works in our body.