6. In the Middle Ages, most scientists believed that the world was made from four simple elements and that almost everything was a mixture.
Which type of pure substance had they not
yet discovered?

Plz help me... I will seriously give you an award for answering correctly :)

chemical properties are the characteristic of matter which can only be observed by changing the chemical identity of a sample like flammability reactivity and toxicity.

c. electrical charges of ionic bonds.

if the temperature drops and becomes cool

then the atmosphere can be freezing as the water vapor in the air is at maximum (100%) and can be severely cold

also can be snowing lightly as the moisture in the air will start to solidify

and btw this is not chemistry but