Question $2(1$ point$)$

Select all that apply. Which of the following sets of organic molecules likely present

in Earths early ecosystem is in order of decreasing complexity?

propionic acid $-->$ acetic acid $-->$ formic acid

none of these

succinate $-->$ formic acid $-->$ hydrogen cyanide

ribulose $-->$ methane $-->$ ribose

acetic acid $-->$ proline $-->$ aldehydes