During primary succession, an ecosystem cannot 're-build' with large trees and bushes. Explain.

List charasteristics of athenosphere

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.

What are the pros and cons of transect sampling?