Analysis of question B: Animal cell culture is to take out the relevant tissues in animals, disperse them into single cells, and then put them into suitable culture medium to let these cells grow and proliferate, so the purpose of animal cell culture is to obtain a large number of animal cells, so A is wrong; Before culture, the cells should be dispersed into single cells with trypsin, and then cultured in a suitable medium, so B is correct; The canceration of cells occurs in the process of subculture, so C is wrong; Cells cultured for 10-50 generations are called cell lines, and cells cultured for 50 generations are called cell lines, so d is wrong. Test center: This topic examines the relevant knowledge of animal cell culture, aiming to examine the candidates' ability to remember and understand the main points of knowledge and grasp the internal relationship between knowledge.