Question 7 of 24
© Macmillan Learning
Which of these atoms, molecules, or groups are part of the heme cofactor?
$\boxed{ }$ Fe$^{3+}$
$\boxed{ }$ Fe$^{2+}$
$\boxed{ }$ pyrrole
$\boxed{ }$ imidazole
$\boxed{ }$ distal histidine
$\boxed{ }$ proximal histidine
$\boxed{ }$ methylene groups linking pyrrole rings
$\boxed{ }$ methylene groups linking imidazole rings