Use the Following Information When Answering the Corresponding Question(s)

question 18

Multiple Choice

Use the following information when answering the corresponding question(s) .
Estrogens found in the environment have raised concerns about effects on reproductive health of animals.Researchers studied the effects that estrogens in the water have on sexual differentiation in zebrafish.They exposed embryo-larval (0-21 days post-hatching) ,juvenile (21-42 days post-hatching) ,and adult (over 200 days post-hatching) fish to three concentrations of 17β-estradiol (5,25,and 100 nanograms/liter) that are within the range of concentrations found in water leaving sewage treatment plants in different countries.They then examined the proportion of males and females when the fish exposed at embryo-larval and juvenile stages reached adulthood.Embryo-larval stage fish that had been exposed to 100 ng/l 17β-estradiol resulted in adult populations that had substantially more females than males compared to control groups.Embryo-larval fish that had been exposed to 5 and 25 ng/l of 17β-estradiol did not show a statistically significant shift in the proportion of females.(Brion,F. ,C.R.Tyler,X.Palazzi,B.Laillet,J.M.Porcher,J.Garric,and P.Flammarion.2004.Impacts of 17β-estradiol,including environmentally relevant concentrations,on reproduction after exposure during embryo-larval-,juvenile-,and adult-life stages in zebrafish (Danio rerio) .Aquatic Toxicology 68:193-217. )
-Refer to the paragraph on the effects of estrogens in the environment.What is the significance of using the concentrations of 5,25,and 100 ng/l of 17β-estradiol for the dose in this experiment?

• A)These concentrations are similar to those found in many animals.
• B)These concentrations are found in the environment.
• C)These concentrations are effective,yet not lethal to the fish.
• D)These concentrations are standard in toxicology assays.

---

Definitions:

Reinforcement

A behavioral principle where the probability of a response occurring is increased or decreased through positive or negative stimuli.

Overtime Pay

Additional compensation provided to employees who work beyond the standard hours prescribed by their contract or work regulation.

Assembly Line

An assembly line is a manufacturing process in which parts are added to a product in a sequential manner to create a finished product efficiently.

Idle

A state of inactivity or not being in use, often referring to machinery or workers.