)A rock is put in a graduated cylinder with initially contained 15.0mL of water. The level rose to 17.5 mL and the rock had a mass of 7.50g. What is the density of the rock to the correct number of significant figures?

  3.0 g/mL

Explanation:

The volume is the difference in water levels:

  17.5 mL -15.0 mL = 2.5 mL

The density is the ratio of mass to volume:

  (7.50 g)/(2.5 mL) = 3.0 g/mL

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Taking the difference of "large" numbers reduces the number of significant figures to 2, so that is the number the answer must use. All other numbers here have 3 significant digits.

c)red bank

explanation:

red bank is a borough in monmouth county, new jersey, incorporated in 1908 and located on the navesink river, the area's original transportation route to the ocean and other ports.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.