The number of types of blood group phenotypes that can be produced by the human blood groups alleles A,B, and O is

Options

A. One
B. Two
C. Three
D. Four

Answer

To determine the number of types of blood group phenotypes that can be produced by the human blood group alleles A, B, and O, we can follow these steps:

### Step 1: Understand the Blood Group Alleles
Human blood groups are determined by three alleles:
- A
- B
- O

### Step 2: Identify Possible Combinations
The combinations of these alleles can lead to different blood group phenotypes. The possible combinations are:
- A (genotype AA or AO)
- B (genotype BB or BO)
- AB (genotype AB)
- O (genotype OO)

### Step 3: List the Blood Group Phenotypes
From the combinations identified, we can list the blood group phenotypes:
1. Blood Group A
2. Blood Group B
3. Blood Group AB
4. Blood Group O

### Step 4: Count the Blood Group Phenotypes
Now, we count the distinct blood group phenotypes we have listed:
- A
- B
- AB
- O

This gives us a total of **4 distinct blood group phenotypes**.

### Conclusion
Thus, the number of types of blood group phenotypes that can be produced by the human blood group alleles A, B, and O is **4**.