Explanation:
The valence electrons determine the group the elements belong in the periodic table. For example, the element sodium, Na, has a valence electron of one and so it belongs to Group 1 in the periodic table. Another example is Aluminium, Al, which has a valence electron of three and therefore it belongs to Group 3 in the periodic table.
Answer:
- Energy is passed from organisms at one trophic level or energy level to organisms in the next trophic level. Producers are always the first trophic level, herbivores the second, the carnivores that eat herbivores the third, and so on.
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A. deoxyribose + phosphate group + thymine
Answer:
b. can be highly variable depending on season and rainfall.
Explanation: