# Function: asBackbone()

[**lifecycle-kit**](https://jonbogaty.com/lifecycle-kit/api/readme/index.md)

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[lifecycle-kit](https://jonbogaty.com/lifecycle-kit/api/readme/index.md) / [chem](https://jonbogaty.com/lifecycle-kit/api/chem/readme/index.md) / asBackbone


# Function: asBackbone() {#function-asbackbone}


> **asBackbone**(`id`, `backbone?`): `Record`\<`string`, `number`\>

Defined in: [chem/biomolecules.ts:129](https://github.com/jbcom/lifecycle-kit/blob/074e4e7b8038d3e2de9eb44c4b5b5aee0ef02b48/src/chem/biomolecules.ts#L129)

A tissue's formula expressed in a given world's backbone.

Carbon atoms become backbone atoms; everything else is untouched. Passing
"C" returns the formula unchanged, which is why every caller can default to
it and worlds that chose carbon cost nothing extra.


## Parameters {#parameters}



### id {#id}


`string`


### backbone? {#backbone}


[`Backbone`](https://jonbogaty.com/lifecycle-kit/api/chem/type-aliases/backbone/index.md) = `"C"`


## Returns {#returns}


`Record`\<`string`, `number`\>