Question

Scientists believe that the Earth's early atmosphere lacked __________ gas because photosynthetic organisms did not yet exist

Answer 1

Scientists believe that the Earth's early atmosphere lacked oxygen because photosynthetic organisms did not yet exist. Hope this helps and have a great day!

Answer 2

The right answer is C. Oxygen

During photosynthesis, there is consumption of carbon dioxide and water to produce glucose and dioxygen. Glucose is the "fuel" of its growth. Cellular respiration will consume some of this glucose and oxygen to form oxygen and water.

So, if the atmosphere was lacking oxygen, it's simply because there was no photosynthesis producing oxygen.