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 explain why this statement is no longer valid?

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Therefore, the statement that says all living things depend on the sun is no longer valid.

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.