According to the current (2005) Dietary Guidelines for Americans:

Question

Quizplus · Accepted Answer

The statement in option D is correct. As people age, their skin becomes less efficient at producing vitamin D when exposed to sunlight. Dark-skinned individuals have more melanin in their skin, which makes it harder to produce vitamin D from sunlight. Therefore, the elderly and individuals with dark skin are at greater risk of low vitamin D concentrations than other populations. Option A is incorrect because the statement is contrary to the truth. Option B is also incorrect because animal sources of iron (heme iron) are more easily absorbed than plant sources (non-heme iron). Option C is incorrect because pregnant women require a higher daily intake of folic acid than women of childbearing age who may become pregnant.

According to the Current (2005) Dietary Guidelines for Americans