Which of the following is not a form of energy heat mechanical solar matter

a.(heat
b.(mechanical
c.(solar
d.(matter

Option D

Explanation:Matter can be defined as the substance having mass, volume and occupy space. Matter is made up of atom which is formed by the combination of subatomic particles.

Matter exists in three states: solid, liquid and gas. These three states of matter are made up of atoms and have volume.  

Energy can be defined as the quantitative property that is transferred from one substance to another which provides the body ability to do work.

Matter is not a form of energy, like that of solar energy, mechanical energy and heat energy.

i think the answer is a.keratin is the pigment responsible for skin color.