Please help it's a select all that apply question I believe and this is also my last attempt I'm a bit confused: Chemistry Entropy

The atomic number, or number, is the described as the number of in the nucleus of an chemical element.

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

Who examines and coordinates the cleanup of polluted sites?