For his science project, austin wants to determine if the ph of standing rainwater changes over time. he collects a jar of rainwater and places it indoors in a spot that does not receive a lot of sunlight to limit evaporation. using a ph testing kit, he measures the ph of the water once a day for 20 days.

what is the independent, or manipulated, variable in austin’s experiment?

a. the number of days the rainwater is allowed to sit
b. the number of times the rainwater is observed
c. the change in the amount of rainwater due to evaporation
d. the change in ph of the rainwater over time

D. The change in pH of the rain water over time.

Explanation:

Im 100% sure. But It just makes the most sense.

imagine a line passing through the center of earth that goes through both the north pole and the south pole. this imaginary line is called an axis. earth spins around its axis, just as a top spins around its spindle. this spinning movement is called earth's rotation. at the same time that the earth spins on its axis, it also orbits, or revolves around the sun. this movement is called revolution.

to figure the total magnification of an image that you are viewing through the microscope is really quite simple. to get the total magnification take the power of the objective (4x, 10x, 40x) and multiply by the power of the eyepiece, (usually 10x)