Is it true that an apple, onion, and a potato all taste the same if you plug your nose

Yes

Explanation:

It is frequently quoted that upwards of 80% of our taste is made up by smell. So if you plug your nose and cover your eyes, the taste between an apple and onion should be indistinguishable. The logic makes sense. ... All potato chip flavors taste the same.

the answer for sodium is 0.186

the answer for rubidium is 0.251

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.