Question

multiple choice question
what is the tough protein of skin that few pathogens can penetrate?

carotene
keratin
collagen
melanin

Explanation:

To solve this, we analyze each option:

• Carotene: A pigment, not a skin - toughing protein.
• Keratin: It is a tough protein in the skin (epidermis) that forms a protective layer, and few pathogens can penetrate it.
• Collagen: Mainly provides structural support in connective tissues, not the tough outer - layer protein of the skin.
• Melanin: A pigment that gives color to the skin and protects from UV, not a tough protein for pathogen resistance.

Answer:

B. Keratin (assuming the options are labeled as A. Carotene, B. Keratin, C. Collagen, D. Melanin)