Grasshoppers have no ears, instead they use an organ called the tympanum located in the first segment of their abdomen, whereas humans take in sound waves through the ear canal until they reach the eardrum. The eardrum picks up the vibrations and then transmits them to tiny bones in the middle of the ear, the bones pass the vibrations to the inner ear (which is filled with liquid) and the cochlea.
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Answer:
Cancer disease occurs when the abnormalities occurs during cell division of stem cells. Stem cells are those cells which are produced in the body and used by the body when the cells are older or get damaged. When the division of these stem cells are uncontrollable, cancer occurs which spread to the surrounding cells. When a large group of cancer cells grow in size, it turns into tumor.
Needles.
Sharing needles or things that you can eject through your skin (ex. drugs)
Infected tattoo needle that wasn't cleaned and disinfected properly