A cross between parents with AaBB and aaBB genotype will form -

Options

A. all AaBB
B. 1 AaBB:3 aaBB
C. 1 AaBB:1 aaBB
D. 3 AaBB: 1 aaBB

Answer

To solve the problem of determining the offspring genotypes from a cross between parents with the genotypes AaBB and aabb, we can follow these steps:

### Step 1: Identify the Parent Genotypes
The genotypes of the parents are:
- Parent 1: AaBB
- Parent 2: aabb

### Step 2: Determine the Gametes Produced by Each Parent
Next, we need to determine the types of gametes that each parent can produce:
- Parent 1 (AaBB) can produce two types of gametes:
- AB (from A and B)
- aB (from a and B)

- Parent 2 (aabb) can produce only one type of gamete:
- ab (from a and b)

### Step 3: Set Up a Punnett Square
Now we can set up a Punnett square to visualize the potential offspring genotypes from the combination of these gametes.

```
| ab
-----------------
AB | AaBb
-----------------
aB | aabb
```

### Step 4: Analyze the Offspring Genotypes
From the Punnett square, we can see the possible offspring genotypes:
1. AaBb
2. aabb

### Step 5: Determine the Ratio of Offspring
The resulting genotypes from the cross are:
- 1 AaBb
- 1 aabb

This gives us a ratio of:
- 1 AaBb : 1 aabb

### Conclusion
The offspring from the cross between AaBB and aabb will form in a ratio of 1:1.

### Final Answer
The correct answer to the question is that the cross will form offspring in a 1:1 ratio.

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