Which of the following statements is true? Group of answer choices The lag period following secondary exposure to an antigen is shorter than the lag period following primary exposure. In the secondary response to an antigen, lower levels of IgM will be detected in an individual’s serum. In the secondary response to an antigen, higher levels of IgM will be detected in an individual’s serum. The lag period following secondary exposure to an antigen is longer than the lag period following primary exposure.