The earliest photosynthesizers probably used what as a source of hydrogen?
A, CO
B. CO2
C. H2S
D. H2O
I think it is C. H2S
To determine the correct answer, we need to understand the process of photosynthesis and the different potential sources of hydrogen.
Photosynthesis is a process used by plants, algae, and some bacteria to convert sunlight, carbon dioxide, and water into glucose (a type of sugar) and oxygen. In this process, hydrogen is obtained from a source and combined with carbon dioxide to form glucose.
The potential sources of hydrogen for early photosynthesizers are:
A. CO: Carbon monoxide is a compound that consists of one carbon atom and one oxygen atom. While it contains carbon, it does not provide hydrogen and is not a suitable source for photosynthesis.
B. CO2: Carbon dioxide is a compound made up of one carbon atom and two oxygen atoms. It does not provide enough hydrogen for photosynthesis.
C. H2S: Hydrogen sulfide is a compound made up of two hydrogen atoms bonded to a sulfur atom. Some bacteria, known as sulfur bacteria, are capable of using hydrogen sulfide as a source of hydrogen during photosynthesis. These bacteria are often found in environments such as deep-sea hydrothermal vents.
D. H2O: Water is made up of two hydrogen atoms bonded to one oxygen atom. Water is the most common and widely available source of hydrogen for photosynthesis. The majority of photosynthetic organisms, including plants and algae, use water as their source of hydrogen.
Therefore, the correct answer is D. H2O, as early photosynthesizers likely used water as their source of hydrogen during photosynthesis.