Why was Darwin hesitant to publish his work?

Darwin was hesitant to publish his work because of what others would think of him. Darwin delayed it by two decades and cared very deeply of what others' thought of him. Darwin was most worried about the reaction of the church authorities and his colleagues that were advanced.

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it’s lava came from an explosive eruption

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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.