Answer:
Reaction between an oxygen and a phosphorus will produce oxides of phosphorus.
Explanation:
Reaction between oxygen and phosphorus produces four atoms of phosphorus with five atoms of oxygen. Sometimes it produces two atoms of phosphorus and five atoms of oxygen and sometimes four atoms of phosphorus and six atoms of oxygen. It does so depending upon the availability of oxygen. The size of phosphorus atom interferes with the ability to form a double bonds to the other elements, such as nitrogen, oxygen, etc.
Unrestricted populations of organisms experience Exponential growth.
As a population reaches is carrying capacity there is an increase in competition for All of the above.
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Classifying compounds as ionic or covalent
If a compound is made from a metal and a non-metal, its bonding will be ionic.
If a compound is made from two non-metals, its bonding will be covalent.
Answer: I. The number of molecules is conserved.
III. Atoms are neither created nor destroyed
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products formed must be equal to the mass of reactants taken.
In order to get the same mass on both sides, the atoms of each element must be balanced on both sides of the chemical equation.
For example: 
Thus in the reactants, there are 4 atoms of hydrogen , 2 atoms of oxygen and 2 atoms of sodium.Thus there will be 4 atoms of hydrogen, 2 atoms of oxygen and 2 atoms of sodium in the product as well.