The toothbrush evolved over time and mainly out of necessity. Traces of the first toothbrush can be dated back as early as 3500 B.C.E. These bamboo sticks were then used just like a modern manual toothbrush to clean the teeth. Eventually, the Chinese version of the toothbrush made its way to Europe.
Answer:
Rocks expand and contract when they are heated and cooled which cause them to break.
Explanation:
This was known as manifest destiny. Colonists believed that is was their right and destiny to complete the westward expansion.
Answer:
If the resin was not applied it would smell horrifically bad
Explanation:
Resin was used to make the are that the body was in smell better.
To help employees function effectively in job situations, a human-factor psychologist designs products that are safe, effective, and easy to use.
