A physical change is when the form of the matter is just altered. While a chemical change results from a chemical reaction. No reaction is happening during the mixing of the two colors [nothing is boiling, freezing, evaporating, melting ext.] , but after you mix them the end result does look different. That only because we changed the physical properties of it.
(B is not a physical change because the baking powder inside of the cake must under go a reaction that causes the cake to rise. )
C. A blue liquid and a yellow liquid mix and make a green liquid.
Explanation:
A physical change is a change in which chemically a substance remains the same but a change in state of matter may occur. It is a reversible change i.e. the substance can be converted into the original state even after the change has occurred. As per option c even if a blue liquid has been mixed with a yellow liquid to produce a green liquid we can still separate both the liquids using a physical method of separation to get the original liquids back.
Other options are wrong because they are examples of chemical change in which the change is irreversible and we can never get the original substance back by any means because a reaction has changed the substance entirely.
A) The independent(test) variable controls the dependent variable. A good way to think about this is that the independent variable has nothing that effects itself. The dependent variable is 'dependent' or reliant on the independent variable.
<h2>Digital thermometer are used these days instead of clinical thermometers because: Digital thermometers are designed to be more accurate. Most digital thermometers have digital screening which extract temperature of wherever you are measuring. </h2>
I believe the answer is carbon dioxide. Because when carbon dioxide and water combine in the atmosphere it forms a very weak acid called carbonic acid, which falls to the Earth's surface as precipitation.
