**Core Concept:** Zinc is an essential trace element required for various physiological processes, including protein synthesis, nucleic acid synthesis, and cell division. It plays a crucial role in immune system function, wound healing, and taste perception. Zinc deficiency can lead to impaired growth, delayed puberty, delayed wound healing, and immune system dysfunction.

**Why the Correct Answer is Right:** The daily requirement of zinc in humans depends on several factors, including age, gender, and body size. Based on the Recommended Dietary Allowances (RDAs) provided by the National Academies of Sciences, Engineering, and Medicine, the daily requirement varies as follows:

1. Infants (0-6 months): 2 mg/day
2. Infants (7-12 months): 3 mg/day
3. Children (1-3 years): 5 mg/day
4. Children (4-8 years): 8 mg/day
5. Children (9-13 years): 11 mg/day
6. Adolescents (14-18 years): 15 mg/day
7. Adults (19-50 years): 8 mg/day
8. Pregnant women: 11 mg/day
9. Lactating women: 12 mg/day

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because it does not match the RDA values provided above, which vary based on age, gender, and body size.
B. This option is incorrect as the daily requirement of zinc varies according to age, gender, and body size, making this choice incorrect.
C. This option is incorrect because it does not match the RDA values provided above, which differ based on age, gender, and body size.
D. This option is incorrect as the daily requirement of zinc varies based on age, gender, and body size, making this choice unsuitable for all age groups.

**Core Concept (Continued):** Zinc is primarily acquired through the diet, with the most significant sources being shellfish, red meat, poultry, and legumes. Additionally, zinc is absorbed from the gastrointestinal tract and transported to various tissues, including the liver, spleen, bone marrow, and pancreas.

**Clinical Pearls:**
1. Zinc supplementation is crucial in patients with zinc deficiency, which can lead to impaired growth, delayed wound healing, and immune system dysfunction.
2. Zinc supplementation has been shown to improve immune function and reduce the duration and severity of respiratory tract infections in children.
3. Zinc supplementation has been demonstrated to improve cognitive function and reduce the duration of diarrhea in children with zinc deficiency.

**Why the Correct Answer is Right:** Option D (8 mg/day) is the correct answer because it represents the daily requirement for adults (19-50 years old) among the provided options, which varies based on age, gender, and body size.

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because the daily requirement of zinc is not specific to pregnant women and does not cover the wide range of ages and body sizes that the other