Why is there free oxygen in the air?
A) Organisms need oxygen to manufacture ATP.
B) Free oxygen has been present since the formation of the earth's atmosphere.
C) Evaporation of the oceans liberated oxygen.
D) It is a by-product of photosynthesis.
Correct Answer:
Verified
Q2: Two principal organelles in eukaryotes that were
Q3: It has been discovered that enzyme-like catalysis
Q4: Eukaryotic cells acquired mitochondria and chloroplasts by
A)endosymbiosis.
B)exocytosis.
C)pinocytosis.
D)mutation.
Q5: The oldest fossils of eukaryotes have been
Q8: The oldest microfossils are of
A)prokaryotes.
B)eukaryotes.
C)insects.
D)pollen grains.
Q9: Which of the following was produced in
Q10: In the original experiments by Stanley Miller
Q11: The early Earth's reducing atmosphere probably contained
Q12: Imagine that NASA discovered a new planet
Q34: Prokaryotic organisms were the only life-forms present
Unlock this Answer For Free Now!
View this answer and more for free by performing one of the following actions
Scan the QR code to install the App and get 2 free unlocks
Unlock quizzes for free by uploading documents