Final answer:
In a covid test kit, the "C" and "T" stripes serve different purposes. The control stripe is used to verify the validity of the test, while the test line is used to determine the presence of antigens in the sample.
Step-by-step explanation:
In the "C" and "T" stripes of a covid test kit, the "C" stripe is the control stripe and the "T" stripe is the test line.
The control stripe is used to verify the validity of the test. It binds any beads present to indicate that the test is working properly. If a color develops at the control line, it means the test is negative.
The test line ("T" stripe) is used to determine the presence of antigens in the sample. If a color develops at the test line, it indicates a positive result, meaning that the antigens have bound to the antibody-coated beads in the first stripe.