The diagram is a simplified model of four Earth systems—the atmosphere, hydrosphere, biosphere, and geosphere—and the changes that their interactions cause. Which statement is MOST USEFUL for explaining or using this model?
A. The causes and effects of a specific global change are confined to one Earth system only.
B. Only one Earth system causes a specific global change, but all Earth systems could be affected.
C. All Earth systems may interact to cause a specific global change, but only one Earth system is affected.
D. Both the causes and effects of global change may involve all Earth systems.

What best explains whether bromine (br) or neon (ne) is more likely to form a covalent bond? bromine forms covalent bonds because it has seven valence electrons, but neon has eight valence electrons and already fulfills the octet rule. bromine forms covalent bonds because it has many electron shells, but neon has only two electron shells and is tightly bound to its electrons. neon forms covalent bonds because it can share its valence electrons, but bromine has seven valence electrons and can gain only one more electron. neon forms covalent bonds because it has only two electron shells, but bromine has many electron shells and will lose electrons in order to fulfill the octet rule.