Severe combined immunodeficiency (scid): a. is a result of the absence of macrophages or b cells b. affects only part of the adaptive immune response. c. can be caused by failure of tap transporters. d. can be caused by failure of vdj recombination. e. all of the above.

"Severe combined immunodeficiency (SCID)" can be caused by "failure of VDJ recombination".  

Option D

Explanation:

"SCID" is "inherited immune system disorder" which happen due to abnormalities in the response of both T and B cells which are needed for the proper functioning of the immune system. VDJ occurs in genetic recombination occurring in the early or developing stages of lymphocytes. Somatic recombination is also a part of VDJ which results in immunoglobulin's, which is "defining feature" of the immune system and the same which causes severe combined immunodeficiency.

Your answer is b. codominant