Answer:
B. liver
Step-by-step explanation:
The immune system is a complex network of organs, tissues, cells, and molecules that work together to defend the body against harmful pathogens, such as bacteria, viruses, fungi, and parasites.
A Mucous membranes: Mucous membranes are part of the immune system as they serve as a physical barrier that helps to trap and prevent pathogens from entering the body. They are found in various areas of the body, including the respiratory tract, gastrointestinal tract, and urogenital tract, and are lined with special cells that produce mucus and immune cells that help fight against pathogens.
B Liver: The liver is not directly part of the immune system. It is primarily responsible for detoxification, metabolism of nutrients, and production of important proteins, such as clotting factors. However, the liver does play a role in the immune response by filtering blood and removing pathogens, toxins, and other harmful substances from circulation.
C Skin: The skin is the body's largest organ and serves as a physical barrier against pathogens, preventing them from entering the body. Additionally, the skin contains specialized immune cells that help defend against pathogens that may breach the skin's barrier, making it an important part of the immune system.
D Saliva: Saliva, which is produced by salivary glands in the mouth, contains enzymes that can help break down food and also has antimicrobial properties that can help inhibit the growth of bacteria and other pathogens in the mouth. While saliva has some immune properties, it is not considered a primary component of the immune system.