Plz help i have a timed quiz

How can antibodies "remember" a particular bacterial invader or "antigen" on that invader?

Which of the following was a characteristic of a dromaeosaur? modified front claw grasping with their forelimbs both a and b 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.