Un ejemplo de investigacion transversal

Which of the following represents the results of a review of well-controlled studies of vitamin c supplementation on the resistance to, and recovery from, colds? there was a reduction in the duration of colds by 50% on the average. there was a slight effect on reducing the duration and severity of colds for people taking vitamin c supplements. there was a significant reduction in the duration of colds in people who consumed at least one gram a day. there was a significant reduction in the number of colds only in people who consumed > three grams per day.

Melanocytes and keratinocytes work together in protecting the skin from uv damage when keratinocytes a. provide the melanocyte with a protective shield against abrasion b. maintain the appropriate temperature so the product of the melanocyte will not denature c. maintain the appropriate ph in order for the melanocyte to synthesize melanin granules d. accumulate the melanin granules on their superficial portion, forming a uv-blocking pigment layer

The first step in treating water from a river or lake is usually