Answer:
The paper no longer has smooth edges
The paper has not produced gas when torn
The paper has not changed colours
The paper is still paper with the same chemical makeup
Answer:
C) Krypton is a noble gas, so it was difficult for chemists to find it, as though it was a secret.
Explanation:
A.
H₃C-CH₃
this is called ethane
B.
H₃C-CH₂-CH₂-CH₃
this is called butane
C.H₃C-CH₂-CH₂-CH₂-CH₂-CH₃
this is called hexane
D.
H₃C-CH₂-CH₂-CH₂-CH₂-CH₂-CH₃
this is called heptane
The answer is either A or C. Sorry I'm not much help :)