The model of the solar system changed, because a. understanding of the solar system changed. b. the order of the planets changed. c. the first model of the solar system was not built to scale d. none of the above

In an experiment examining the effects tai chi on arthritis pain, callahan (2010) selected a large sample of individuals with doctor-diagnosed arthritis. half of the participants immediately began a tai chi course and the other half (the control group) waited 8 weeks before beginning. at the end of 8 weeks, the individuals who had experienced tai chi had less arthritis pain that those who had not participated in the course.

Drag each tile to the correct box. the body monitors the levels of oxygen in the blood to regulate breathing. isabel is running in a marathon and is near the finish line. she feels out of breath. how will her nervous system work to generate a reaction? arrange the tiles in chronological order. isabel's breathing rate increases. sensory receptors in the arteries detect low oxygen levels. the brain sends signals through motor neurons. sensory neurons generate an impulse. the central nervous system relays an impulse to certain brain regions.

Color blindedness is a sex-linked trait. if we could see the pedigree chart for several more generations of the family illustrated here, we would expect a) more males to be color blind. eliminate b) more females to be color blind. c) no females to ever be color blind. d) an equal number of males and females that are color blind.