Diploblastic and triploblastic are terms that describe

Options

A. the number of invaginations during embroyonic development
B. the number of germinal layers during embryonic development
C. the number of germinal layers during embryonic development
D. the number of cell types during development.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Terms:**
- The terms "diploblastic" and "triploblastic" refer to the number of germ layers present during the embryonic development of an organism.

2. **Embryonic Development:**
- During embryonic development, organisms form germ layers which are the foundational layers that develop into various tissues and organs.

3. **Germ Layers:**
- There are three primary germ layers:
- **Ectoderm:** The outermost layer, which develops into the skin and nervous system.
- **Mesoderm:** The middle layer, which forms muscles, bones, and the circulatory system.
- **Endoderm:** The innermost layer, which develops into the digestive system and other internal organs.

4. **Diploblastic Organisms:**
- Diploblastic organisms are those that develop only two germ layers: ectoderm and endoderm. They do not have a mesoderm layer.
- Example: Organisms in the phylum Porifera (e.g., sponges) are considered diploblastic.

5. **Triploblastic Organisms:**
- Triploblastic organisms develop all three germ layers: ectoderm, mesoderm, and endoderm.
- Example: Organisms in the phylum Platyhelminthes (e.g., flatworms) are considered triploblastic.

6. **Conclusion:**
- Therefore, the terms diploblastic and triploblastic describe the number of germinal layers during embryonic development. The correct answer is that these terms refer to the number of germinal layers during the development.