Thomas constructs a model by completing the following steps. 1. Draw a diagram that shows where oxygen is found on Earth, including the atmosphere, bodies of water, land, and living things.
2. Draw arrows to show how oxygen moves and changes form from one location to another.
3. Label each arrow.

Thomas has constructed an example of what type of ecological model?
A. biogeochemical cycle
B. food web
C. energy pyramid
D. geological system

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.