WBCs in vertebrates are in _______function,

Explanation

**Step-by-Step Solution:**

1. **Understanding WBCs**: WBCs, or White Blood Cells, are a crucial component of the immune system in vertebrates. They play a significant role in protecting the body against infections and diseases.

2. **Function of WBCs**: The primary function of WBCs is to provide protection. They are often referred to as the "soldiers" of the body because they defend against pathogens like bacteria and viruses.

3. **Mechanism of Action**: WBCs utilize a process called phagocytosis, where they engulf and digest harmful microorganisms. This is a key aspect of their protective function.

...