Answer;
Antibodies.
The human immune system fights infection by releasing antibodies.
Explanation;
The immune system acts to defend the body against pathogens such as viruses, bacteria and fungi that may cause a disease.
It does so using various types of mechanism, one is by the production of antibodies.
Antibodies are proteins that are produced by the B-cell and are used by the immune system to identify and neutralize pathogens.
These antibodies also activates proteins known as complements which assist in the killing of bacteria, viruses and the infected cells.
1. Naked Seeds, Gymnosperm means 'naked seed' and these were the earliest trees to evolve. They do not produce flowers and have seeds which are directly exposed to the air for wind pollination. Pine cones are one example. For ease you might think of the gymnosperms as conifers, such as yew and Scots pine.
Not entire sure because I haven't taken human anatomy but I'd guess it would have to be the digestive enzymes breaking it down