Answer:
Calcium is a chemical element with the symbol Ca and atomic number 20.
Explanation:
<span>Valence is defined as number of electrons that are present in the outermost orbital. Oxygen is in the 16th column of the periodic table and the total number of valance electrons is determined by units place digit of the column position which is 6 for oxygen. The outermost orbital is the high energy level and there are two in that orbit. So the valance is +2.</span>
Answer= Because polar bears depend on ice as a habitat to survive the more the temperature is rising and the sea ice melting as a result of global warming there is basically a possibility that the population of polar bears will decline because there will be no home (habitat)left for them to breed(survive)in.
Answer:
the outer planets are primarily composed of gasses. also the outer planets are considerably bigger than the inner ones
