How can you determine that a star is about to turn into a red giant
a. what a large amount of helium has turned into hydrogen
b. when the pressure inside the star exceeds its temperature
c. when the star falls into the sun
d. when a large amount of hydrogen has been turned into helium
need ! will give brainliest

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.

yes the answer is total mass in unchanged   : )