Suppose that during any period of ¼ second there is one instant at which the crests or troughs of component waves are exactly in phase and maximum reinforcement occurs. how many beats will occur in 1 second?           a. 8   b. 12   c. 2   d. 4

Which statement is true regarding weathering in dry environments? a) chemical weathering is absent because of a lack of humidity. b) physical weathering is usually more evident than chemical weathering. c) it is impossible to identify the type of weathering that has occurred. d) physical weathering does not play a significant role in dry environments.