What is a closed system ?

In a closed system

$ Biosphere is a closed system ! Closed vascular bundles are having intrafascicular cambium.

Assertion :- Entropy is always constant for a closed system. Reason :- Closed system is always reversible.

The male reproductive system is often referred to as a closed system, whereas the female reproductive system is referred to as an open system. To what aspect(s) of the system does this refer? Explain.

What is the difference between an open system and a closed system?

"Closed system" is