Answered

The table shows a section of DNA taken from four different organisms.

\begin{tabular}{|c|c|c|c|c|c|c|c|c|c|c|}
\hline
Organism & \multicolumn{10}{|c|}{Base Sequence} \\
\hline
W & C & A & C & A & A & T & C & G & A & A \\
X & G & T & C & A & A & T & G & G & T & G \\
Y & C & T & C & A & A & T & C & G & T & A \\
Z & C & T & C & A & T & T & C & G & T & A \\
\hline
\end{tabular}

Which two organisms are the most distantly related to each other?

A. W and X
B. W and Z
C. X and Y
D. X and Z



Answer :

GinnyAnswer
To determine which two organisms are the most distantly related to each other, we need to compare their DNA sequences and count the number of differences between each pair. The more differences there are, the more distantly related the organisms are.

Let's compare each pair step-by-step:

1. Comparing W and X:
```
W: C A C A A T C G A A
X: G T C A A T G G T G
```
Differences:
- Position 1: C ≠ G
- Position 2: A ≠ T
- Position 7: C ≠ G
- Position 9: A ≠ T
- Position 10: A ≠ G

Total differences: 5

2. Comparing W and Y:
```
W: C A C A A T C G A A
Y: C T C A A T C G T A
```
Differences:
- Position 2: A ≠ T
- Position 9: A ≠ T

Total differences: 2

3. Comparing W and Z:
```
W: C A C A A T C G A A
Z: C T C A T T C G T A
```
Differences:
- Position 2: A ≠ T
- Position 5: A ≠ T
- Position 9: A ≠ T

Total differences: 3

4. Comparing X and Y:
```
X: G T C A A T G G T G
Y: C T C A A T C G T A
```
Differences:
- Position 1: G ≠ C
- Position 7: G ≠ C
- Position 10: G ≠ A

Total differences: 3

5. Comparing X and Z:
```
X: G T C A A T G G T G
Z: C T C A T T C G T A
```
Differences:
- Position 1: G ≠ C
- Position 5: A ≠ T
- Position 7: G ≠ C
- Position 10: G ≠ A

Total differences: 4

6. Comparing Y and Z:
```
Y: C T C A A T C G T A
Z: C T C A T T C G T A
```
Differences:
- Position 5: A ≠ T

Total differences: 1

After comparing all pairs, we find the maximum number of differences is 5. Therefore, the two organisms that are most distantly related are W and X.

The correct answer is:
A) W and X

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