¿En qué grupo de sustancias químicas se incluye a la Hemoglobina?

"HEMOGLOBINA. Las características de la hemoglobina (Hb) como amortiguador están íntimamente vinculadas a la capacidad de disociación del grupo imidazólico del aminoácido histidina unido al hierro que contiene el grupo hemo (ver figura inferior)."

Link: http://www.ehu.eus/biomoleculas/buffers/buffer4.htm#:~:text=HEMOGLOBINA&text=Las%20caracter%C3%ADsticas%20de%20la%20hemoglobina,hemo%20(ver%20figura%20inferior).

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance