The blood then flows through the <span>open tricuspid valve. </span>
It takes to much energy and there's a lot of dirt
Answer:
A circuit is a closed loop that electrons can travel in. A source of electricity, such as a battery, provides electrical energy in the circuit. Generally, there is some appliance that uses electricity in the circuit. The appliance may, for example, provide light or heat or mechanical energy.
Explanation:
The two are potassium and rubidium. Why? Na is an alkali metal. As you go down the metals become more reactive.
Calcium has 20 protons. Why? The atomic # is 20 (the one at the top).
It has 20 neutrons. Why? The atomic mass (the number on the bottom) is ~40, ignoring electron mass. 40- 20 protons = 20 neutrons.
It has 20 electrons.
Why? The # of protons and electrons is the same. Ions aren't on the periodic table.
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