Answer:

heme

Answer	Crossword Clue
HEME	Deep-red blood pigment
HEME	Blood pigment
HEME	Iron-rich blood pigment

HEME	Hemoglobin pigment.
HEME	Deep red
HEME	Red pigment
HEME	Iron-containing pigment
HEME	Myoglobin component
HEME	Red blood cell component
HEME	Complex, red organic pigment
HEME	Blood component

HEME	Deep red blood pigment
HEME	Complex red organic pigment
HEME	Iron carrier in blood
HEME	Deep red pigment
HEME	Pigment in red blood cells

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.