Which of these energy sources is formed from decayed and compressed plankton?
A. Natural gas
B. Biomass
C. Geothermal
D. Coal

The answer is b i think

Particle exchange energy though elastic collision , hope this .

Change in speed or direction : )

It is a mixture. simply put, a compound must be pure, that is, of only one chemical structure and composition. a mixture is made of different chemical substances (i.e. elements, molecules, compounds) that are not chemically bonded to each other, but instead physically grouped together, as in the case of gasoline (a homogeneous solution).