Answer:
The correct answer is D. proliferation and differentiation.
Explanation:
Primary immune response occurs due to the first exposure of an antigen to the immune system. The primary immune response is generally delayed by many days because it takes time for B and T cells to become cloned and to proliferate and differentiate.
Then after several days of proliferation and differentiation of activated T and B cells, T cells become effector T cells and B cell becomes plasma cells which then eliminates the antigen. Memory B and T cells are also produced during this process which helps in generating a quick immune response during the second and subsequent exposure of that antigen.
So the correct answer is D. proliferation and differentiation.
Correct answer: A). Forecasting weather
A weather radar is an instrument that is used to locate precipitation, calculate its motion and determine the type i.e hail, snow or rain. It sends electromagnetic energy pulse into the atmosphere. If that pulse of energy interacts with something, then it reflects back the energy, which can be sensed by the weather radar.
Nowadays, most radar used are Doppler effect, which has dual polarization, it determines that movement is toward or away from the radar.
Hence, the correct answer would be option A.
