Question

scientists have been monitoring co₂ in the atmosphere from mauna loa in hawaii since 1958. which of the following units is used by scientists to measure co₂ in the atmosphere? a dobson units b percent saturation c parts per million d ph

Explanation:

Dobson units measure ozone layer thickness. Percent saturation is often used for dissolved substances in a liquid - gas context like oxygen in water. pH measures acidity or basicity. Parts per million (ppm) is a common unit for measuring the concentration of trace gases like $CO_2$ in the atmosphere.

Answer:

C. Parts per million