1. The body of a person or other mammal is a complex organism. The structure of the body has several levels of organization. Which of the following lists the structural levels of the body from smallest to largest? * A. cell → tissue → organ → organ system → organism
B. cell → organ → organ system → tissue → organism
C. organ → organ system → cell → tissue → organism
D. organ → organ system → tissue → cell → organism

the answer would be A.

Explanation:

this would be because a cell is the smallest living thing, after cells, tissues are the next smallest thing, then it is an organ, because different tissues make up an organ, then multiple organs will create an organ system, and multiple organ systems create an organism.

answer; the tunica intima also called tunica interna, consists of elastic fibers,connective tissue and smooth muscle cells;