45) B) Vaporizing water at its boiling point
46) D) There is no change in temperature
47) B) Molecules must be pulled apart
48) D) Steam at 100 C
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In the periodic table, calcium is located at the 2nd column of the 4th row starting from the hydrogen gas.
Calcium is very essential in the human body is it helps maintain a healthy teeth and all other bones. Other calcium are also found in nerves, tissues, and all other parts. Calcium also helps in clotting blood and normalizing a person's heart beat. This may apply not only to humans but to all living things.
An isotope is an atom with a different number of neutrons than another atom of the same element. Since atoms of the same element all have the same number of protons, choice B(6pro &6neu vs. 6pro&7neu) is an example of isotopes
The objects density is greater than one