Answer: 
Explanation:
Combustion is a chemical reaction in which hydrocarbons are burnt in the presence of oxygen to give carbon dioxide and water.
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.
The balanced combustion reaction is,:

<span>At the atomic scale, the kinetic energy of atoms and molecules is sometimes referred to as heat energy. Kinetic energy is also related to the concept of temperature. Temperature is defined as the measure of the average speed of atoms and molecules. The higher the temperature, the faster these particles of matter move.</span>
I think the answer is (1) Co. Because the element of Cobalt also has 2 electrons at the outer layer which is the same as Calcium. And the outer layer is an important factor which can affect the property of an element.
Answer:
Towards this goal, this project aims to develop a statistical measure of the uncertainty of the decisions made on the friction ridge evidence (i.e., evidential value of fingerprint comparison), which ultimately can be referred to as a scientific basis of the identification decisions made in friction ridge analysis.
Explanation:
I believe the correct answer is <span>that it emphasizes the curious tone of the speaker.
The speaker is interested in what is going on on that urn, what is depicted there and why. He wants to have answers to many of his questions because he is curious, and this is why he is constantly repeating the interrogative word what.
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