Answer:
You either are referring to the fish Chordate, or the animal classification. In the case of the classification it is literally any animal that has developed any sort of dorsal fin, for example some snakes can fall under this classification.
Answer:
We have to conserve water because we need it live.
Explanation:
We use water to clean ourselves, drink, and use in foods.
Malthus didn't account for diseases or natural disasters in his theory of population growth.
The correct answer is outer electrons. These are sometimes called 'valence electrons', and they are responsible for the element's properties and how it forms bonds. For example, elements in Column 2 are likely to form ionic bonds with elements in Column 16. This is because elements in Column 2 have 2 outer electrons, while elements in Column 16 have 6 outer electrons. If the element in Column 2 gives its 2 electrons to the element in Column 16, then the former will be stable because the energy level underneath will be complete, and the latter will be stable because it will have a complete outer energy level with 8 electrons.
Hope this helps!