Read the passage carefully and answer the questions based on the passage:

Passage: Species diversity on earth is not uniformly distributed. It is generally highest in the tropics and decreases towards the poles. Earth’s fossil history reveals the incidence of mass extinctions in the past. Earth’s rich biodiversity is vital for the very survival of mankind.

It is believed that communities with high diversity tend to be less variable and more productive. The reasons of conserving biodiversity are narrowly utilitarian, broadly utilitarian and ethical. Biodiversity conservation may be in situ as well as ex-situ.

How many episodes of mass extinction of species have occurred since the origin and diversification of life on earth?

The correct option is Five.

Step-by-Step Explanation:

1. Understanding the Context:
The question asks about the number of mass extinction episodes that have occurred since the origin and diversification of life on Earth.

2. Historical Extinction Events (The "Big Five"):
According to geological and fossil records, Earth has witnessed five major episodes of mass extinctions before the current era (often referred to as the sixth extinction, which is currently ongoing due to human activities). These five historical mass extinctions are:
• Ordovician-Silurian extinction (approx. 440 million years ago)
• Late Devonian extinction (approx. 365 million years ago)
• Permian-Triassic extinction (approx. 250 million years ago)
• Triassic-Jurassic extinction (approx. 210 million years ago)
• Cretaceous-Paleogene extinction (approx. 66 million years ago)

3. Conclusion:
Since the origin and diversification of life on Earth, there have been exactly five episodes of mass extinction. Therefore, the option "Five" is the correct choice.