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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
<span>A. genetic variation in species
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The reason animals need a continuous supply of oxygen is to<u> Obtain energy from their food.</u>
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The most fundamental reason why animals need a non-stop delivery of oxygen is without it animals can't achieve sufficient power from their meals.
Cells require a steady delivery of power to generate and preserve the biological order that keeps them alive. This electricity is derived from the chemical bond energy in food molecules, which thereby function as fuel for cells.
The animal's metabolism converts oxygen into strength. All through this system, a waste gas called carbon dioxide is produced. To remove it, the carbon dioxide is carried lower back to the lungs, where its miles are collected and exhaled.
Learn more about metabolism here: brainly.com/question/461228
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