Early conditions on earth were high temperature, volcanic eruptions, lightning and reducing atmosphere (because there was no oxygen) , so an organism which can survive in these extreme conditions might have lived at early earth. from given options chemoheterotrophs fit right in the given situations. so the answer is chemoheterotrophs.

Explanation:

Chemoheterotrophs were the first life forms on Earth. These were anaerobic organisms that lived in anoxic environments and relied on inorganic molecules for energy. They evolved around 3.8 billion years ago and were the only life forms on Earth for almost 2 billion years.

Chemoheterotrophs:

Chemoheterotrophs are organisms that use organic compounds as a source of energy and carbon. They obtain energy by breaking down organic molecules through the process of cellular respiration. This process involves the use of enzymes to break down glucose and other organic compounds into smaller molecules, releasing energy in the form of ATP.

Evolution of Life:

The evolution of life on Earth can be divided into three main stages:

1. Chemical evolution: This stage began around 4.5 billion years ago with the formation of the Earth and the solar system. During this stage, simple organic molecules such as amino acids and sugars were formed.

2. Biological evolution: This stage began around 3.8 billion years ago with the appearance of chemoheterotrophic organisms. These organisms evolved into autotrophs, which were able to produce their own food through photosynthesis.

3. Cultural evolution: This stage began with the emergence of humans around 200,000 years ago. Humans have developed complex cultures and technologies that have transformed the world around them.

Conclusion:

In conclusion, chemoheterotrophs were the first life forms on Earth. These organisms evolved around 3.8 billion years ago and were the only life forms on Earth for almost 2 billion years. They were anaerobic and relied on inorganic molecules for energy. Over time, these organisms evolved into autotrophs, which were able to produce their own food through photosynthesis.