Charles Darwin was a Geologist, biologist and is best known for his contributions to science of evolution.
The answer is A track star speeding up as he sprints to the finish line.
The whitening toothpastes showed differences in their physical-chemical properties. All toothpastes promoted changes to the surface, probably by the use of a bleaching agent.
GaBr3
Gallium=Ga
Bromine= Br
Bromide=Br3
