Answer to Question 1
Answer: The key to the body's successful immune system is the ability to distinguish self (or proteins that belong to its body) from non-self (proteins that belong to any other living thing).
Answer to Question 2
Answer: Cytotoxic T cells directly kill virus-infected cells and tumor cells. Helper T cells secrete proteins that promote inflammation by calling for the microphages to the site, stimulating B cells, and activating the cytotoxic T cells. Regulatory T cells help lower the immune response once the infection is under control. Memory T cells remember an antigen and therefore can produce new fighting cells rapidly.
The vagina, sagittal section showing the location of the vagina and its relationship to the cervix,
Organs of the digestive system.
CRISPR-Cas9 System for In Vivo Genome Editing Experiments
Color monitor for a computer system.
The cardiovascular system.
Coolant flow through a typical engine cooling system.