Excluding water and fat, the human body is made up almost entirely of protein. Protein is the main component of muscles, bones, organs, skin, and nails. Excluding water, muscles are composed of about 80% protein, making this nutrient especially important for athletes.

Astudent pours 10.0 g of salt into a container of water and observes the amount of time it takes for the salt to dissolve. she then repeats the process using the same amounts of salt and water but this time she slowly stirs the mixture while it is dissolving. the student performs the experiment one more time but this time she stirs the mixture rapidly. the dependent variable in this experiment is: time for salt to dissolve speed of stirring amount of water mass of salt