Any chemical or physical change that absorbs energy 1. cannot occur spontaneously. 2. forms products with less mass than the initial reactants. 3. is an endothermic process. 4. has high activation energy.

3. is an endothermic process.

Explanation:

Generally, reactions can be classified into two. Depending on whether they absorb heat -energy or release energy.

Endothermic Reactions are those reactions in which the reaction absorb heat form the surroundings.

Exothermic reactions are those reactions that release heat to the surroundings.

This means the correct option is;

3. is an endothermic process.

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