Which plant is used to make pain-relieving drugs?

$A$ cultivated plant whose seed epidermis produces abundant cellulosic hairs used in the textile industry and the manufacture of fine-quality paper is:

The botanical name of tea is:

The cheapest high energy fruit crop of India is

$Withania somnifera$ is the botanical name of:

The plant which is used as a source of spice as well as dye is