Multiple choice

The outermost cell layer of an organism is ____.

  1. epithelium

  2. elastin

  3. epidermis

  4. erythrocytes

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The epidermis is the outermost layer of cells in multicellular organisms, serving as the protective barrier against environmental factors. It prevents water loss and protects against pathogens. Elastin is a protein, erythrocytes are red blood cells, and epithelium is a broader tissue category.