That's easy. The only really true answer is your age. Because, smoke and heat can be trapped and made to go around and around in a room. A person's height can, with age, diminish.
A helium balloon can still have helium in it when it begins to descend. But, a person can never become younger. They may look younger with help from plastic surgery or chemicals. But, their true age can never be taken away.
The correct answer is age because as soon as you are born your not one yet but the next year you will be one you have aged from just being born to being one years old so however said height is wrong because people shrink
when they get older or they just stop growing and become smaller or shorter but all these answers are wright because all of you said age in your answers every person is a smart and inteligent person.
However, there could be more answers to this same riddle as height and time also lie in the same list. These three things, age, time, and height don't come back once they are gone until and unless we die and come back to starta new life.
That's why it is said about the time, "Time is more valuable than money, you can get more money but you cannot get more time".
The Sun stays in one spot. It's the Earth that orbits around the Sun and teases your eyes.
You can never get younger. Age is a popular and right answer and there is not a time machine ''yet''. Height is the wrong answer. If you have seen your mom/ dad old, you're taller than them. Try it now.
Entropy. Perhaps this is one of the most difficult concepts to understand, with which you can meet in a physics course, at least if we talk about classical physics. Few graduates of physics departments can explain what it is. Most problems with understanding entropy, however, can be removed if one thing is understood. Entropy is qualitatively different from other thermodynamic quantities: such as pressure, volume or internal energy, because it is not a property of the system, but of how we consider this system.
Unfortunately, in the course of thermodynamics, it is usually considered along with other thermodynamic functions, which exacerbates misunderstanding.
There are actually many possible answers to this, depending on where you are from. For me, I think the only one that goes up but never goes down is age. It is apparent that people age every year, and this goes up every year. The only time when a person’s age will not go up anymore is when a person dies.
It is not possible for a person’s age to go down. There are a lot of people who are scared of aging, probably because they usually associate age with being ugly or not being attractive. Over the years, it has become more established that people can become beautiful at any age.