Question

One theory of early life on Earth states that the first life forms did not use oxygen for respiration and were unable to make their own food. Based on this theory, which types of organisms were most likely present?

aerobic, autotrophic bacteria


aerobic, heterotrophic bacteria


anaerobic, autotrophic bacteria


anaerobic, heterotrophic bacteria

Answer 1

Anaerobic, heterotrophic bacteria

Step-by-step explanation:

i got it right on k12

Answer 2

Early organisms would have to be anaerobic, as air was likely non existent. This rules out the first two options.

Autotrophic can be called producers, and heterotrophic can be called consumers.

The question states that "did not use oxygen for respiration and were unable to make their own food"

Only one option satisfies the question:

anaerobic, heterotrophic bacteria