A watershed model shows the effect/direction/path of rainwater on a certain area. This makes it especially useful to predict which areas are susceptible to floods and droughts. I'd say, based on this, that the correct answer is B. <span>It helps forecast the amount of precipitation at different locations.
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<u>Answer</u>
D. She should increase the number of coils in the primary winding.
<u>Explanation</u>
A transformer is a device that is used to step down or step up a the voltage.
It has two coils, primary and secondary that are used to determine how much the voltage changes.
To decrease the voltage the ratio of number of coils in the primary to the number of coils in the secondary should be big.
To reduce the voltage, D. She should increase the number of coils in the primary winding.