Behavior is actually more complicated than innate or learned. Most behaviors are a mix of the two, neither completely innate nor entirely learned. For instance, some innate behaviors -- such as flying in insects -- can be perfected over time and through experience.
the nucleolus is a prominent sub nuclear structure that is not bound by a membrane and resides within the nuclear matrixthough known to exist since the eighteenth century the primary function of the nucleolus was not discovered until the 1960she nucleolus is a prominent sub nuclear structure that is not bound by a membrane and resides within the nuclear matrix
Through the microscope, the nucleolus looks like a large dark spot within the nucleus. A nucleus may contain up to four nucleoli, but within each species the number of nucleoli is fixed. After a cell divides, a nucleolus is formed when chromosomes are brought together into nucleolar organizing regions. During cell division, the nucleolus disappears. Some studies suggest that the nucleolus may be involved with cellular aging and, therefore, may affect the senescence of an organism.