Which of the following is NOT a condition believed to have been present on early Earth, leading to the formation of organic molecules?

A. High levels of free oxygen

B. High concentrations of carbon dioxide

C. Presence of simple molecules like methane and ammonia

D. Frequent lightning storms

Why are viruses not considered living organisms?

A. They can replicate independently

B. They lack cellular structure

C. They can perform metabolic processes

D. They respond to their environment

Which of the following is NOT a challenge in explaining the spontaneous origin of cells?

A. Formation of simple organic molecules

B. Creation of a genetic code

C. Development of a metabolism

D. Instant formation of modern cells