Could you help me know what these plants lack, wha...

Fertiliser give her Fertiliser

That is a nitrogen deficiency. Maybe, something else is going on but these particular symptoms are incredibly obvious and easy to diagnose.

Oxygen, carbon, hydrogen. Let's start with basics.

These look like clone cuttings to me, in which case yellowing is common while the cuttings make roots. The old yellowed growth rarely goes green again but if new growth appears ok then don't worry.

You do understand that you can't grow an elephant in a tea cup.......... No diary + limited info = impossible to give meaningful, accurate advice. Under fed, over watered, poor drainage, tiny pots, clear plastic cups, wrong pH, wrong nutrients...........could be any one of those, a few of those or all of those..........but without a lot more info or a diary, impossible to say exactly.

I think there could be several issues. What do you feed her? Also it looks like you might have ph fluctuations