Question

Scientists used to say that all living things depend on the sun. Explain why this statement is no longer valid?

Answer 1

Because plants and fish that live deep in the ocean (depths of the ocean) rely not on the sun but heat radiation and oxygen from volcanic landforms on the ocean floor

Answer 2

Scientists used to say that all living things depend on the sun because that time microbes and animals under deep sea and hydrothermal vents were not discovered.

Deep-sea and caves are the limited places where sunlight does not penetrate but life flourish there. They are mostly microorganism which get their energy by underwater volcanic vents and even do not require oxygen to survive.

These microorganisms obtain energy by chemosynthesis. It is the process in which microbes utilize chemicals released by hydrothermal vent like hydrogen sulfide, ammonia, and other chemicals to obtain energy.

Therefore, the statement that says all living things depend on the sun is no longer valid.