What is the iron (II) ion? How does it differ from the iron (III) ion

This is a coral reef ecosystem. many biotic and abiotic factors affect the health of this ecosystem. which set correctly pairs a biotic factor and an abiotic factor?

Which of these statements is false? a. others may notice a problem with a relationship before the people involved. b. the first sign of a problem with a relationship is a feeling of anger. c. damaged relationships can be repaired. d. even good relationships can be damaged.

Me the formula cacl2 represents the compound