The idea that the eye contains three kinds of photoreceptors differentially sensitive to red, green, and blue that are responsible for color vision was proposed by the German physiologist

Research indicates that the link between family size and children's IQ can be explained by the

A) Flynn effect. B) strong trend for mothers lower in intelligence to give birth to more children. C) strong trend for mothers higher in intelligence to give birth to more children. D) growing use of birth control techniques.

Which of the following pose the most significant health risks among school-aged children?

A) Infectious diseases, such as colds and influenza B) Accidents and obesity C) Stress D) Environmental toxins and pollutants