Answer: The correct answer is black because the product of its side and mass is lower.
Explanation: Density of a substance is defined as the mount of matter that can be stored in a given volume.
Mathematically,

As, density is inversely proportional to the volume of the substance.
The substance will be more denser if it has less volume and it will be less denser if the volume is more.
We are given two cubes having different sides.
Volume of the cube is calculated by using the formula:

where, a = side of the cube.
Black: The side of this cube is 2 and volume will be =
Yellow: The side of this cube is 3 and volume will be =
As, the volume of black cube is less. So, this cube will be more denser.
Density of black cube: 
Density of Yellow Cube: 
Hence, black cube will be more denser because the product of its side and mass is lower.
Answer:
Boiling point.
Explanation:
This is because when water boils, it is changing from a liquid to a gas. This is a state change/physical change.
I hope I helped!
I think the answer is the last option or D) but i think i am wrong
Answer:
C) Practicing good scientific method and practices.
Explanation:
The text states, "repeating the experiment multiple times," as well as other preparations that a good scientist uses.
Doing something multiple times over is a good sign of a good scientific method.
Taking careful measurements, having several researchers run the same experiment, and only testing one variable at a time are all good practices that a scientist should use.
<em> </em><em><u>The</u></em><em><u> </u></em><em><u>correct</u></em><em><u> </u></em><em><u>answer</u></em><em><u> </u></em><em><u>is</u></em><em><u> </u></em><em><u>C</u></em><em><u>)</u></em><em><u>.</u></em>
A constant in an experiment is <u>B. </u><span><u>the quantity that must remain the same</u>. If it is constant, it doesn't change, so it cannot be variable. D makes no sense.
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