Which organism is most specialized? a. bacteria b. unicellular algae c. cat d. ant

The answer would be (C.cat) because For the cat has the most advanced biological system, whereas the unicellular algae and bacteria are microscopic in size, and while the ant does have a system and is a multi-cellular organism, the cat has a much more advanced biological system with many more functions and organs. 

Hope it helps! 

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.