Aglass harmonica was invented by benjamin franklin and is known as the franklin harmonica. it consists of glass bowls of varying sizes filled with different amounts of water. this instrument was popular in the 1800s. which detail is least relevant to someone researching benjamin franklin’s genius? the instrument was popular in the 1800s. the bowls varied in size and were filled with different amounts of water. the harmonica consisted of glass bowls and water. franklin invented a glass harmonica.

the present continuous is a verb tense which is mainly used to indicates that an action is in progress at the moment of speaking.  

it is formed using: person + verb to be (am/is/are) +verb + - ing form  

example: i am studying at this moment .

in addition, the present continuous is also used in order to express things that will or will not happen in the near future.

example: i am having dinner with some friends tonight.

the speaker sometimes   uses it   to express that an action is repeated and it causes irritation on the part of the speaker

example: my sister is constantly complaining about everything.