Answer:
The functional group
Explanation:
A functional group defines a hydrocarbon. an ester the functional group is an O- alkyl group while that one of an alcohol is -OH group. An aldehyde is a functional group on its own.
Heat can be absorbed or produced
Answer:
Described by a redox reaction below
Explanation:
Iron(III) oxide is an ionic compound, since it consists of a metal, iron, and a nonmetal, oxygen.
Ionic compounds are formed when metals lose their valence electrons in order to have an octet in their previous shell and donate them to nonmetal atoms, so that nonmetals fill their outer shell to have an octet.
As a result, positive ions (cations) and negative ions (anions) are formed. When iron reacts with oxygen, the following reaction takes place:

This is a redox (oxidation–reduction) reaction, since we have electron loss and gain. Four iron atoms lose a total of 12 electrons to obtain a +3 charge in the final compound, while 3 oxygen molecules gain these 12 electrons to become 6 oxide anions with a -2 charge.
Answer:
Lysosomes
The function of a lysosome is to rid of any unwanted waste. Acid hydrolase aids in that process. Therefore, the acid would make the most sense to be found in lysosomes.