Answer:
Organs can be grouped by their function, these groups are called systems.
many types of tissues can combine to form an organ,
and
many organs grouped together are called tissue
In 1798 the first smallpox vaccine was developed.Over the 18th and 19th centuries,systematic implementation of mass smallpox immunization culminated in its global eradication in 1979.
It depends on the person, but I know that the average cycle is about 28 days long, and it only occurs once a month, in normal situations.
Hope this helps! :)
Stay smart,
~Mistermistyeyed.
Refers to human development that is meant to involve all the parts of a person.
