I think it's Letter c.13 if I'm not mistaken
Chromium is a metal in nature. So when one chromium is
bonded to another chromium, there is a weak intermolecular forces which helds
them together which we call as “metallic bonding”.
Metallic bonding is the intermolecular force of attraction which
exist between valence electrons and the metal atoms. It is considered as the
sharing of various detached electrons between many positive ions, whereby the
electrons serve as a "glue" which gives the substance a definite
structure.
Answer: The answer is Fossil A is younger than the index fossil.
Explanation: Because it’s the newest layer
