Which factor determines the pattern and speed of cleavage?

Explanation

### Step-by-Step Solution:

1. **Understanding Cleavage**: Cleavage is the process of cell division that occurs after fertilization, leading to the formation of a multicellular embryo. The pattern and speed of cleavage can vary significantly among different organisms.

2. **Types of Cleavage**: There are several patterns of cleavage:
- **Radial Cleavage**: This type occurs when the cells divide symmetrically around a central axis. It allows for equal division of cells and is often seen in organisms like echinoderms.
- **Spiral Cleavage**: In this pattern, cells divide in a spiral arrangement, which is typical in organisms such as annelids. The cells do not align directly on top of each other.
- **Bilateral Cleavage**: This occurs when the cleavage plane divides the embryo into two equal halves, which is characteristic of tunicates.
...