25
arteries near the heart expand as blood rushes in after each contraction. which component in the arteries allows this expansion?

a. connective tissue in the tunica media
b. smooth muscle in the tunica media
c. endothelium in the tunica intima
d. elastin protein in the tunica intima

B. Smooth muscle in the tunica media

Explanation:

Arteries contains elastic and smooth muscle fibers that helps in contraction and expansion, respectively. The smooth muscle fibers are present in the tunica intima which is the thickest and middle layer of arteries.

Connective tissues and endothelium don't play a direct role in contraction or expansion. However, elastin proteins helps in contraction.

Hope this help.