Why do compounds form in nature?

answer by yourhope:

how do models compare to real-world objects?

d. most models represent a real-world object in a simpler way.

: )

the awnser is group 12

air

in a tire you fill a tire with air

then a couple days later you check the air pressure in the tire

hope this mark me brainliest

yes the answer is total mass in unchanged   : )