organ-like structures in a cell
A root cell would contain organelles such as nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, and vacuoles. These organelles play various roles in the growth, metabolism, and storage functions of the root cell.
Organs are made up of tissues, which are made up of cells. Cells are "living things," so yes, organs are living.
these are the mitochondria and chloroplasts and it is because they have their own DNA, mRNA, tRNA, ribosomes and they replicate by binary fission so they are said to be self governing. Semi autonomous means they want to leave but they are in a symbiotic relationship with the cell and have evolved to become part of it.