Me !
select the two systems that are most closely related to the situation or process described (thinking about a big test and getting a stomachache )
nervous*
digestive
circulatory
immune
select the two systems that are most closely related to the situation or process described (eating lean protein before a big race )
respiratory
digestive
nervous
muscular

The answer to the first one is Digestive and Nervous system.

The answer to the second one is Digestive and Muscular system.

Hope it helped.

 Can you choose mine as the brainliest answer.

a researcher conducts an experiment on the secretion of a particular hormone in mice. scientists inject mice with a substance that stimulates the production of the hormone. the scientists then test the levels of hormones produced by the mice. the tool used to measure the hormones consistently detects the levels at 10 points lower than the actual hormone levels in the mice. this tool makes measurements, but the measurements aren't .

explanation:

no u

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.

here's your answer.