The development of haploid cells of gametophyte into a haploid sporophyte is called:

Options

A. apogamy
B. apospory
C. budding
D. binary fission

Answer

**Step-by-Step Solution:**

1. **Understanding the Terms:**
- First, we need to clarify the terms involved in the question. The term "haploid" refers to cells that have a single set of chromosomes (n), while "diploid" refers to cells with two sets of chromosomes (2n).

2. **Identifying the Process:**
- The question asks about the development of haploid cells of a gametophyte into a haploid sporophyte. In plant biology, the gametophyte is the stage that produces gametes (sex cells), and the sporophyte is the stage that produces spores.

3. **Analyzing the Options:**
- **Option A: Epogamy** - This refers to the process where haploid cells develop into a haploid sporophyte. This matches the question's requirement.
- **Option B: Epospory** - This involves the development of diploid cells, which does not fit the question.
- **Option C: Budding** - This is a form of asexual reproduction where a new organism develops from a bud on the parent. It is not related to the development of gametophytes or sporophytes.
- **Option D: Binary Fission** - This is a method of asexual reproduction where a single organism divides into two daughter cells. It does not pertain to the development of gametophytes or sporophytes.

4. **Conclusion:**
- Based on the analysis of the options, the correct answer to the question is **Epogamy**. This process specifically describes the development of haploid cells from a gametophyte into a haploid sporophyte.

**Final Answer:** Epogamy

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