Ruminants Like Cows Rely on Bacteria in Their Stomachs to Break

Ruminants like cows rely on bacteria in their stomachs to break down the cellulose in the plants they eat. This has ___________. (Select all that apply)

A) Released large amounts of methane gas into the atmosphere due to cow flatulence and belching
B) Greatly exacerbated the problem of global warming because CH₄ is almost 20X better at trapping atmospheric heat than CO₂
C) Resulted in lowered global oxygen levels due to the bacterial respiration
D) Resulted in lowered global CO₂ levels due to bacterial respiration