I think it’s A or c but I’m not so sure
Manipulative experiments alter levels of a predictor variable (or factor), and then measures how one or more variables respond to these alterations. ... Natural experiments-An observational study in which we take advantage of natural variation that is present in the variable of interest.
B) they have thick, pleated stems
The answer is C as the genetic correspond with the order of the nucleotides
C. Amino Acids.
Proteins consist of strands of amino acids, which is produced in the ribosomes of the cell.
