What do scientists usually do when a scientific problem first arises?

Scientists usually raise a hypothesis based on their knowledge and previous observations. This hypothesis will be tested by an experiment.

This hypothesis arises from the research question posed by the researchers.This initial hypothesis is also called null hypothesis and will be accompanied by alternate hypotheses

b. the carbon cycle ensures living things have a source of hydrogen

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

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