The answer of the question is
B. Exfoliation
A vaccine uses a live pathogen that is too weak to make you sick. Once it enters your body you defeat it easily. Now that yur body is familiar with it your body can fight off the disease in the future.
Both gymnosperms and angiosperms have vascular tissue that is specialized for transport of minerals, water, and organic compounds. Also, both gymnosperms and angiosperms have seeds. The only difference is that angiosperms have seeds hidden in the ovary while gymnosperms have seed on the surface of the scales of the cones.
I'd say, ina general way, that the most imporant cells in defense against parasitic organisms are definitely white blood cels, the cells responsible for defeating antigens, pathogens and deseases.
Although these might be the most important ones in that specific task (defending against parasitic organisms), all the cells in the immune system, along with other non-cell things are important, since they all play a specific role indispensable in our immune system.
Hope it helped,
BioTeacher101
