<span>A. Helium </span>atomic number 2
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The answer should be "by convection" not by radiation.
About 7-8 years More. The real answer would be 7.14285714286
Chemical
bonds between atoms in reactants undergo change during a chemical
reaction.
<span>The substance (or substances) initially involved in a </span>chemical reaction<span> <span>are
called reactants or reagents. </span></span>Chemical reactions<span> <span>are
usually characterized by a </span></span>chemical<span> change,
and they yield one or more products, which usually have properties different
from the reactants.</span>
The correct answer between all
the choices given is the last choice or letter D. I am hoping that this answer
has satisfied your query and it will be able to help you in your endeavor, and
if you would like, feel free to ask another question.