Question

which is one factor that internally influences the onset of puberty?
○ exposure to toxins
○ nutrition
○ hormone levels
○ social stressors

Explanation:

To determine the internal factor influencing puberty onset:

• "Exposure to toxins" is an external environmental factor.
• "Nutrition" (if considering internal, but often has external aspects; however, among options, "hormone levels" is a direct internal biological factor as hormones regulate puberty.
• "Social stressors" are external social factors.

Hormone levels (like gonadotropins, sex hormones) are internal physiological factors driving puberty.

Answer:

C. hormone levels