The minimum amount of energy that has to be added to start a reaction is the activation energy, which starts the reaction. It activates it.
The awnser is Hydrogen. It had the greatest average atomic mass
Answer: Thus
is a secondary alkanol.
Explanation:
Alkanol are compounds which contains carbons bonded by single bonds and contains hydroxy (-OH) as functional group.
Primary alkanol are those compounds which contain hydroxyl group attached a carbon which is further attached to a single carbon atom. Example:
and 
Secondary alkanol are those compounds which contain hydroxyl group attached to a carbon which is further attached to two more carbon atoms.Example:
Tertiary alkanol are those compounds which contain hydroxyl group attached to a carbon which is further attached to three more carbon atoms. Example: 
Thus
is a secondary alkanol.
What objects are we referring to?