Alex is writing an article on primitive people. He has to write about the use of biomass in primitive times.
What should he write?
A. Primitive people used stones as tools.
B. Primitive people used animals as pets.
C. Primitive people used wood as a source of energy.
D. Primitive people used coal for cooking food.

What does resonance result in? quieter sounds frequency amplitude louder sounds

In iceland, the mid atlantic ridge runs through the center of the contry. what can you conclude about the apperence of iceland many thousands of years from now?

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.