Question

What matter is prominently present in a red giant?

Answer 1

in red giant star I think so plasma is present ...
these are generally small stars with a large lifespan...

Answer 2

the red super giant mainly consists of plasma I.e nuclear split off from a atom ,and also the fourth state of matter. But if it is talked about element it mainly consists of hydrogen atoms ,which is continuously fusing to form other complex elements like oxygen ,helium ,iron ,carbon ,etc..