The esophagus, stomach, and intestine together are part of a level of organization called:

Organs. The third level of cell organization. As explained, cell is the basic unit or element in every living organism. By which, is the smallest component and when grouped forms tissues, hence when tissues are grouped they form the organs and when organs group together they form the organ system and thus, the organism. Furthermore, esophagus, stomach, intestines, and the accessory organs are all part of the system called the digestive system of a living organism. Digestive system then is responsible for absorption and metabolism of food and delivers nutrients throughout the body.

answer: - b cells

explanation: -

there are many types of white blood cells present in our body. one such class of white blood cells are the lymphocytes. the b cells belong to the lymphocyte class of wbcs. the b cells perform their action against the pathogen by producing specialised proteins called as antibodies. these antibodies are produced as and when the b cells encounter pathogens in response to the antigens present on the surface of the pathogen. these antibodies bind to the antigens present on the pathogen and then, target them for destruction by other cells of the immune system.

so, the b cells mediate their action by identifying the antigens present on the surface of the pathogens and then producing antibodies in return to mediate its effect.