B2

Physical - Respiratory tract lined with mucus and cilla.

Skin acts a barrier When we get cut, Platelets are used

Platelets - Tiny fragments that are used for clotting. Proteins used for sticking

Chemical - Tears have enzymes

Stomach - HCl

Waxy cuticle that acts as a waterproof barrier found in leaves.

Water doesn't come in in case of pathogens entering or any infection in general.

Cell Wall - Filled with Cellulose that acts like a physical barrier.

If pathogens do enter the plant, plant produces antimicrobial substances as a chemical defence.

Phagocytosis - White blood cell engulfs the foreign cell.

Lymphocytes - Produce antibodies

Antitoxins -  Limit damage done by invading pathogens.