Answer:
its a) trees and forests and b) aquatic biodiversity
The element with the greatest number of valence electrons available for bonding is chlorine. Among all the choices, chlorine is the element that belongs to the higher group number, group 7. Selenium is from group 6. Boron is from group 5, while calcium is from 2. Since the group number also equates to the number of valence electrons, chlorine is the answer.
