All of the cells in the body need oxygen. Hemoglobin molecules in red blood cells transport oxygen through the bloodstream. Oxygen is loaded onto hemoglobin molecules in the lungs and unloaded from the hemoglobin molecules in the tissues.
What drives the unloading of oxygen from hemoglobin molecules in the tissues?

A. the low partial pressure of oxygen in the tissues
B. the high partial pressure of carbon dioxide in the tissues
C. the low partial pressure of carbon dioxide in the tissues
D. the high partial pressure of oxygen in the tissues

Option B) the high partial pressure of carbon dioxide in the tissues.

Explanation:

The high concentration of oxygen in the alveoli of the lungs unloads H+ and carbon dioxide (CO2) from the hemoglobin, just as the high concentration of H+ and CO2 in active tissues unloads Oxygen from hemoglobin molecules.

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

some sources quote the lethal dose, for an average 170lbs opiate-naive individual is between 75 and 375 mg