Which of the following statements accurately describe components of the innate immune response? Select all that apply.

The innate immune system is made up of many parts that work together quickly to fight infection. First, physical barriers such as the skin and mucous membranes stop many germs from entering the body. If a pathogen gets past these barriers, cells like macrophages and neutrophils rush in to engulf and destroy it, while natural killer cells attack infected cells. The complement system, a group of proteins that circulate in the blood, can also directly attack microbes or help other cells recognize and destroy them. Together, these components form a fast, non‑specific defense that protects the body before the adaptive immune system is activated.