After reading the paragraphs below, answer the questions that follow.
Recent studies suggest that flame retardants, chemicals that are used to slow down burning, can mimic estrogen hormones found in the human body. Scientists investigating this phenomenon developed three-dimensional images to show how the chemical structure of certain flame retardants allows the retardants to bind to and inhibit an enzyme (estrogen sulfotransferase) that metabolizes estrogen.
Suppose the scientists want to conduct a study of the effects of flame retardants on estrogen levels. In a hypothetical study, the scientists use frogs to test the effects of flame retardants because the frogs' skin is highly permeable and therefore allows for easy absorption of chemicals.
The scientists collected 20 wild adult frogs and brought them to a laboratory. Ten of the frogs (group 1: five male and five female) were kept in tanks mimicking their natural environment. The other ten frogs (group 2: five male, five female) were kept in tanks like those of group 1 except they were introduced to low amounts of flame retardants in the shallow water in their tank. Estrogen levels were measured on the first day of the experiment and then every 4 days for 20 days.
Results of the experiment yield the data shown in the following graph. What is one overall conclusion that you can draw from these results?
The figure shows the percentage of male and female frogs with flame retardants in their blood in two groups: Group 1 was not exposed to flame retardants, and group 2 was exposed to low doses.◦ As compared to the group 1 male frogs, group 1 female frogs had a lower percentage of frogs with high retardant levels.
◦ As compared to the group 2 male frogs, there was a lower percentage of group 2 female frogs with high levels of flame retardants in their blood.
◦ There was no noticeable difference between the male and female frogs in group 2 in percentage of frogs with high retardant levels.
◦ As compared to the group 2 female frogs, there was a lower percentage of group 2 male frogs with high levels of flame retardants in their blood.