When Did the First Eukaryotic Cells Form

question 2

Multiple Choice

When did the first eukaryotic cells form?

• A)2.1 thousand years ago
• B)2.1 million years ago
• C)2.1 billion years ago
• D)3.7 billion years ago

---

Definitions:

Absorption

The process by which substances are taken up into or across tissues, such as the absorption of nutrients by the intestines.

Gingivitis

A common and mild form of gum disease (periodontal disease) that causes irritation, redness, and swelling (inflammation) of your gingiva, the part of your gum around the base of your teeth.

Periodontitis

A serious gum infection that damages the soft tissue and destroys the bone supporting teeth, potentially leading to tooth loss.

Mucosa

A moist, inner lining of some organs and body cavities, such as the nose, mouth, lungs, and stomach.