What does plant cell needs and what don't they need?
and why

Plant cells, along with every other cell, needs oxygen,carbon, and nitrogen. These are basically the elements every living cell needs to survive.

Plant cells also need sunlight for photosynthesis and produce sugar to convert that into food. 

Most smaller stars don't have a radiative zone.

Engineers have contribute to society in many ways like making the technology we use today or any type of power energy material