is a genetic variation associated with characteristic facial appearance, learning disabilities, and physical abnormalities such as heart valve disease.

Down syndrome

Explanation:

Down syndrome is a genetic disorder that occurs when an abnormal cell division results in an extra copy of chromosome 21. Some symptoms of this syndrome are distinct facial features (small ears, small head, flat face, etc.), short height and even heat defects.

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what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.

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