If natural selection operates to select for a specific trait which statement must be true about that trait for evolution to occur

(99 points) be serious! how do farts work? how do you fart without it stinking? serious answers only

Which of the following is a good strategy when it comes to desserts

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.