In present times, the origin of life is not possible from inorganic compounds due to:
1. Non-availability of raw material
2. High concentration of O₂ in the atmosphere
3. Decrease in temperature
4. Excess of pollution

The concept of chemical evolution is based on:

After about how many years of the formation of the earth, life appeared on this planet?

1. 500 billion years

2. 50 million years

3. 500 million years

4. 50 billion years