Characteristics of Thallophyta​

The earth consists of a variety of different organisms. despite their diversity, however, some similarities on the structural and metabolic levels may be seen. these similarities can be attributed to a. similarities among organisms in their proteins and nucleic acids. b. the ability of organisms to readily adapt to sudden environmental changes. c. similarities in organisms' habitats and niches. d. the ability of all organisms to interbreed and produce new species.

What noticeable trend from this graph might be used to make a conclusion?

What element is able to combine with itself and hydrogen to form large molecules ?