If the human body is 70% water, and water is 2/3 hydrogen, why are humans often called carbon-based lifeforms?

Answer 1

Because Carbon forms the backbone of biology for all life on Earth. Complex molecules are made up of carbon bonded with other elements, especially Oxygen , Hydrogen and Nitrogen .It is these elements that living organisms need, among others, and carbon is able to bond with all of these because of its four valence electrons.
The Human body is a combination of elements and compounds. The average adult (specifically a 70 kilogram adult) is composed of:
Oxygen 65% Carbon 18% Hydrogen10% Nitrogen 3%

Answer 2

If you look at it as building blocks, or a foundation to a building at the very bottom you get the foundation which is what carbon is to us it is the most basic building block for all life on earth and if we didnt have carbon we wouldnt exist or we wouldnt be called carbon based life forms. To answer the 70% water thing, think of the body as a piece of construction equipment (i.e. front loader, or dump truck) they all have grease or some kind of lub and they also have coolent so that the engines in them dont over heat, thus the water acts as both thats why we are 70% water there are other reasons to this you will find better answers in a human bio book, human anatimy book.

Answer 3

There are only two serious candidates that can form the wide variety of molecules with other elements that are necessary for cells and therefore for life. They are carbon and silicon (below Carbon in the Periodic Table and therefore with similar properties to it.) Because they both have a valency of four (can make four bonds with other atoms), However Carbon, the 6th most abundant element throughout the Universe is ten times more common than Silicon (mainly because everything is formed from nuclear fusion of hydrogen and elements with higher atomic weight are formed in smaller quantities as a result), The earth is relatively rich in silicon but despite that, carbon-based life-forms were the ones that formed here.

Answer 4

It's in comparison with silicon based lifeforms from Science Fiction and similar. They've got loads of hydrogen and oxygen in them too so what's left?

Answer 5

Because all the interesting chemistry is carbon based. Water is just filler.

Answer 6

Most compounds in the body contain carbon. We also need carbon-based compounds to respire.

Answer 7

Well it has more to do with the structure of DNA. Than what the container holds. Ceramic coffee cup has more coffee in it than ceramic outside, ya know.

Answer 8

because, silly. I f you squeeze a human hard enough, they will fart diamond dust