For a patient, a doctor prescribes glasses with a converging lens having a power of 4.0 d. you may want to review ( pages 603 - 606) . part a is the patient nearsighted or farsighted?

The patient is FARSIGHTED.
Farsightedness is an eye condition in which the affected individual is able to see objects in the distance very clearly but he can not see objects that are nearby very clearly. Farsightedness always occur because, the images that are suppose to be focused on the retina are instead focused at the back of the retina. To correct this error, the patient needs a converging lens of appropriate power that will help the eyes to refract the light and focus it on the retina.

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.