I don't know why you got down voted for this. I agree. The tone of a question rises at the end of the word if it's used by itself, or the last couple words of the interrogative phrase. Same as in English.
Once I learned that nouns can be classified as "count nouns" or "noncount nouns." Count nouns are like apple, house, idea, dream. Noncount nouns are like water, sugar, love. So, count nouns can either be singular or plural-- that is, you can count them. Noncount nouns can't be counted, and they're all classified as singular.
Use "cuanto" for all noncount nouns.
Use "cuantos" for all count nouns that are plural.
* Note: some people argue that noncount nouns such as water can be counted, as in "How many cups of water?" However, they are counting the cups rather than the water itself.
Not quite; cuanto is singular and cuantos is plural. Kind of weird thinking about how many of one thing there is, but this article really helps: http://www.spanishdict.com/answers/3857/cuanto-cuantos