Between 1884 (the year Mendel died) and 1888 details of mitosis and meiosis were reported, the cell nucleus was identified as the location of the genetic material, and "qualities" were even proposed to be transmitted on chromosomes to daughter cells at mitosis. In 1903 Walter Sutton and Theodore Boveri formally proposed that chromosomes contain the genes. The Chromosome Theory of Inheritance is one of the foundations of genetics and explains the physical reality of Mendel's principles of inheritance.
0.230cm should be the correct conversion
Dendrites and axons.
Dendrites and axons are extensions/fibers in nerve cells that either recive or send information to neurons respectively.
→ The image below shows you both and more parts of a nerve cell.
Hope it helped,
BioTeacher101