An embryo that has developed for about 10 weeks is known as a _________.

Options

A. foetus
B. zygote
C. gamete
D. placenta

Answer

To answer the question, "An embryo that has developed for about 10 weeks is known as a _________", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Development Stages**:
- After fertilization, the first stage is the zygote, which is a single cell (2n).
- The zygote undergoes cell division (mitosis) and develops into an embryo.

2. **Time Frame of Development**:
- The question specifies that we are looking for a term for an embryo that has developed for about 10 weeks.
- Typically, the embryonic stage lasts for about 8 weeks (or 2 months) after fertilization.

3. **Transition from Embryo to Fetus**:
- After approximately 8 weeks, the developing organism transitions from being called an embryo to being called a fetus.
- Therefore, by the 10-week mark, the embryo is referred to as a fetus.

4. **Final Answer**:
- An embryo that has developed for about 10 weeks is known as a **fetus**.