Which type of relationship do cactus wrens and cholla cacti
demonstrate?

There is a commensalistic relationship between the cholla cactus and wren. Relationship: Commensalism is a relationship in which one of the organism's benefits (gets what it needs) while the other organism neither benefits nor is harmed.

Explanation:

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what do the different brain waves do?

explanation:

brainwaves are produced by synchronised electrical pulses from masses of neurons communicating with each other. brainwaves are detected using sensors placed on the scalp. brainwave speed is measured in hertz (cycles per second) and they are divided into bands delineating slow, moderate, and fast waves.