A. Cilia: The core of cilia and flagella is called the axoneme, which possesses microtubules running parallel to the long axis . B. Endoplasmic Reticulum: Ribosomes are associated with the surface of the rough endoplasmic reticulum, where they are involved in protein synthesis . C. Mitochondria: The inner membrane of mitochondria forms a number of infoldings called cristae towards the matrix . D. Kinetochore: Spindle fibres (microtubules) attach to the disc-shaped structures called kinetochores present on the centromere of chromosomes during cell division , .