An old bone contains 80% of its original carbon-14.

c

step-by-step explanation:

c

explanation:

infrared radiation has wavelength in the range between 700 nm and 1 mm. lets' convert these values into scientific notation, keeping in mind that:

let's start from the lower value, we have:

(we moved the dot two places to the left, so we increased the exponent by 2 units, from -9 to -7)

the higher value is:

so, the range of wavelength of infrared radiation is:

6 cars because if you have 8 and subtract 2 youll have 6 left over