Why does a cell membrane have to be made of two layers, rather than just one?

Which sentence is an example of a strong conclusion to an autobiography? a. i stayed after school three days in a row to practice onstage in the auditorium. b. i knew i would have to practice all week to memorize my dance for the recital. c. after the recital was over, i knew practicing was worth it, and i was looking forward to my next big challenge. d. on opening night, i danced in front of a packed auditorium.

What are the seven economic and social goals?

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.