Question

What are examples of non-specific defenses?

Answer 1

Mechanical Barriers
When our hand touches a table, the bacteria on the table do not infect us. Why not? Because they cannot enter our bodies due to the presence and design of our skin. Skin and other membranes (like the cornea and the olfactory epithelium) are physical barriers against infection.
Chemical Barriers

The human body secretes chemicals that destroy infectious agents before they can infect us. For example, you learned that our tears contain the enzyme, lysozyme. Lysozyme kills bacteria. That is a chemical barrier to entry of infectious agents through our eyes. We also secrete chemicals in our digestive system that attack potential harmful substances we ingested with our food.
Fever

Fevers decrease the spread of infection within our bodies in a roundabout way. You see, as our temperature rises, our liver and spleen sequester iron (they hold onto it rather than putting it back out into the blood). As the general blood iron levels decrease, it makes iron less available to the infectious agents. It turns out that bacteria and fungus need more iron in warmer temperatures. Therefore, by decreasing iron levels with a fever, we decrease the ability of bacteria and fungus to survive in our fevered bodies.
Inflammation

When we do have some sort of tissue damage, like a cut in our skin, that opens the door for infection to occur. However, that door is quickly shut by our inflammation response. You have already learned about inflammation. So you should understand that any entry of foreign material through tissue damage will be met by increased leukocyte interactions at that damaged area. You also know that the clotting process occurs, which surrounds the damaged area with a thick barrier of fibrin filaments; therefore, the infectious agents cannot get past the clot.
Phagocytosis

Any foreign material that encounters a macrophage or neutrophil will be quickly ingested by those cells through phagocytosis. Phagocytosis allows these cells to destroy the invasive materials. So, anything that slips past our mechanical and chemical barriers, is not affected by or exposed to fever, and doesn't get caught in the inflammatory response, will most likely be destroyed by phagocytosis.
from: http://faculty.stcc.edu/AandP/AP/AP2pages/Units21to23/immune/nonspeci.htm

Answer 2

its called non specific because there is no specific antigen targeted as it is in third line of defense when T helper cells are activated, and B cells too get activated
and all this is done to target a particular antigen which is causing chaos in the body
for example: bacteria, virus