In some algae, one large, non-motile female gamete fuse with smaller, motile male gamete. Such a type of reproduction is called:

Options

A. Isogamy
B. Anisogamy
C. Oogamy
D. Gametangial contact

Answer

To answer the question regarding the type of reproduction in some algae where one large, non-motile female gamete fuses with a smaller, motile male gamete, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Types of Gametes**:
- In algae, gametes can vary in size and motility. There are three main types of sexual reproduction based on the characteristics of these gametes: isogamy, anisogamy, and oogamy.

2. **Define Isogamy**:
- Isogamy refers to a type of reproduction where the gametes involved are of similar size and shape. Both gametes can be motile or non-motile, but they are equal in size.

3. **Define Anisogamy**:
- Anisogamy is characterized by the fusion of gametes that are of different sizes. In this case, the male gamete is typically smaller and motile, while the female gamete is larger and may be non-motile.

4. **Define Oogamy**:
- Oogamy is a specific type of anisogamy where there is a distinct difference in size and motility between the gametes. In this case, the female gamete is large and non-motile, while the male gamete is small and motile.

5. **Apply Definitions to the Question**:
- The question specifies that there is one large, non-motile female gamete and one smaller, motile male gamete. This matches the definition of oogamy.

6. **Conclusion**:
- Therefore, the type of reproduction described in the question is called **oogamy**.

### Final Answer:
The type of reproduction in some algae where one large, non-motile female gamete fuses with a smaller, motile male gamete is called **oogamy**.