<h2>
A) </h2>
to observe both solutions before the reaction
Answer:
Explanation:
Hello!
In this case, we can notice that among the given ions, Mg2+ and Cr4+ are cations and I- and O2- are anions, thus, for each resulting compound we switch the oxidation states as subscripts to get:
Best regards!
Index fossils are from species that only existed for a short period of time. they are found in rocky layers, Trilobites and Graptolites are index fossils. A guide and zone fossil are used often to determine the age of the rock layer in which it is found.