Cells are the most simple level of organization, as tissues contain cells, organs contain tissues and systems contain organs, so R would be your answer.
Inferior mesenteric artery
The part of the colon located distal to the left colic flexure is derived from the hindgut is supplied by the inferior mesenteric artery. The distal part (lower third of the rectum) is supplied by the internal iliac artery. The ileocolic artery supplying the cecum is a branch of the superior mesenteric artery.
Answer is B since it uses strains and differential transformation to see
Intradermal means pertaining within the skin.