Answer:
C. H and O
Explanation:
Almost 99% of the human body's mass is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium and phosphorus, in that order.
Element Symbol % in body
Oxygen O 65.0
Coal C 18.5
The human body is composed of 60% water, that is, H2O.
Animals likes the sun's energy. The sun supplies energy to plants to help them grow for animals. Animals eat the plants to get the energy they need.
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After two half-lives or 60 years, 7.5 g of the element will be left.
<u>Explanation:</u>
<u>Half-life:</u>
- In simple words, Half-life can be defined as the amount of time needed for a quantity to fall to half its value as contained at the beginning of the time period.
- In this problem the half-life of the element is thirty years, then after thirty years half of the sample would have decayed and half would be left as it is.
- After thirty years (The first half-life ) 30 /2 = 15 g declines and 15 g remains disappeared.
- And after another sixty years (The two half-lives) 15 /2 = 7.5 g declines and 7.5 g remains disappeared.
- After two half-lives or 60 years, 7.5 g of the element will be left.
Parasympathetic will return her heartbeat back to normal. This nervous system is responsible for regulating the body's unconscious actions, and stabilizes it.
It is a that is what I think
