Please, observe that it is not right to say that a substance content heat.
Heat is not something that a body or substance content. Heat is the transmission of energy due to difference of temperatures.
An endothermic reactions is that where the reactants abosorb energy from the surroundings to occur. The products, then, will be higher in energy than the reactants while the surroundings get colder.
Answer:
Isomers are defined as the molecules or polyatomic ions which have similar molecular formula but different in arrangements of atoms.
Isomers can be found in food items carrying glucose (C6H12O6), galactose or fructose, they all have the same chemical formula but differ structurally and chemically.
Glucose is found in vegetables and milk, galactose found in dairy products, and Fructose is found in fruit juices.
This is called
Nuclear fusion
Example is two hydrogen atoms fuse to form a helium atom
Where some of the atoms of hydrogen turn in to energy
So the answer is A