sentences: an nation of pluto something is logs a capital & a sink of light can be used to light something ->  a source of heat can be used to heat a building  a source of heat can be used to heat a building & artificial oil is a sink of light by shade ->  natural gas is used for heating building by burning  natural gas is used for heating building by burning & a office is a mean of capital ->  natural gas is used for heating homes by burning  hatch particle are a nonrenewable switch & artificial oil is a mean of discard hunt ->  natural gas is a nonrenewable resource  natural gas is used for heating homes by burning & natural gas is a nonrenewable resource -> natural gas is a nonrenewable resource that is used for heating homes