Which plant cell structures could not be seen when using 10x objective of a compound microscpe

Structures such as the ribosome, endoplasmic reticulum, and mitochondria cannot be viewed by the 10x objective lens. These organelles are too small to be viewed with low magnification and require over 2000x magnification. At low magnification structures such as the cell wall, vacuoles, and cytoplasm can be viewed.

a saline water is fed to a reverse osmosis unit at flow rate o rotameter connected to reject (retentate) line reads 8 installed in reject and permeate line reads 15.2 milli siemens/cm and 300 micro siemens/com respectively.