Question

information
clues to a crime
a strand of hair. a drop of blood. a footprint. clues like these can help solve a crime. but understanding these clues can be a problem. what is the evidence really showing? forensic science helps people put together all of the evidence to solve a crime. different kinds of evidence are analyzed for important clues. one type of evidence that is very important in solving crimes is deoxyribonucleic acid, which is commonly called dna. almost all the cells in a human body contain dna. no two people have the same dna. therefore, dna samples can help identify the people who were at a crime scene. people who commit crimes may try to keep fingerprints from being left behind at a crime scene. it is much harder for them to keep dna from being left behind. when a person sneezes, spits out a piece of gum, or loses a single hair, the person may leave behind traces of dna. forensic scientists can compare the dna samples from a crime scene to the dna of any suspects or victims. they can also check a computer database that has dna samples from people who were arrested for other crimes.
question 1
what is the purpose of this text?
select one:
a. to inform about the problem of increased crime
b. to identify different types of forensic evidence
c. to explain how dna is used to solve crimes
d. to describe what dna is
question 2
why does the author use the word \therefore\ in the text?
select one:
a. to emphasize that using dna is not always accurate
b. to link the ideas that people have different dna and it can be used to identify criminals
c. to show that dna has limited uses
d. to introduce an argument that is the opposite of the previous argument
question 3
what is the meaning of the word traces in the text?
when a person sneezes, spits out a piece of gum, or loses a single hair, the person may leave behind traces of dna.
select one:
a. valuable pieces
b. large samples
c. unimportant information
d. small amounts

Explanation:

• Question 1: The text mainly talks about different kinds of forensic evidence like hair, blood, foot - prints and focuses on DNA as an important forensic evidence for solving crimes. It doesn't discuss increased crime, only mentions DNA briefly in the context of forensic evidence, not its general description. So it is to identify different types of forensic evidence.
• Question 2: The author first states that no two people have the same DNA, and then says DNA samples can help identify people at a crime scene. The word "Therefore" is used to link these two ideas.
• Question 3: The context mentions sneezing, spitting out gum or losing a single hair as ways a person may leave behind "traces" of DNA. These actions suggest small amounts of DNA are left behind.

Answer:

Question 1: B. to identify different types of forensic evidence
Question 2: B. to link the ideas that people have different DNA, and it can be used to identify criminals
Question 3: D. small amounts