Question

question:
your ____ is responsible for transporting oxygen to tissues in the body that need it.

answer input:
spelling counts but capitalization doesnt.

Explanation:

The circulatory system component that carries oxygen to body tissues is blood, specifically the red blood cells within it, but the most direct single term fitting the context is blood (or cardiovascular system, but blood is the key transport medium here; alternatively, red blood cells, but blood is the standard answer for this fill-in).

Answer:

blood