Incorrect relationship regarding all types of living species is

Options

A. A + G = C+T
B. A + G = C + U
C. (A + T)/(C + G) = 1
D. `(A+T)/(C+G)ne0`

Answer

To solve the question regarding the incorrect relationship among the given options about living species, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Chargaff's Rules**:
- Chargaff's rules state that in DNA, the amount of adenine (A) is equal to thymine (T), and the amount of guanine (G) is equal to cytosine (C). This can be summarized as:
- A = T
- G = C
- Additionally, the total amount of purines (A + G) is equal to the total amount of pyrimidines (C + T).

2. **Analyze Each Option**:
- **Option 1**: A + G = C + T
- This is correct according to Chargaff's rules.
- **Option 2**: A + G = C + U
- This is incorrect because uracil (U) is found in RNA, not DNA. In DNA, we have thymine (T), not uracil (U). Hence, this option is not universally applicable to all living species.
- **Option 3**: (A + T) / (C + G) = 1
- This suggests that the sum of adenine and thymine equals the sum of cytosine and guanine, which is not necessarily true according to Chargaff's findings.
- **Option 4**: (A + T) / (C + G) ≠ 0
- This statement is generally true since A, T, C, and G are all positive quantities in DNA.

3. **Identify the Incorrect Relationship**:
- Based on the analysis, Option 3 is incorrect because it implies a relationship that is not supported by Chargaff's rules.

### Final Answer:
The incorrect relationship regarding all types of living species is **Option 3: (A + T) / (C + G) = 1**.

---