Answer:
A. Integumentary system
Explanation:
The integumentary system consists of the skin,hair and nail. This system consists of the largest organ in the body. The skin helps in protection against pathogens by shielding the internal body system from external objects.
The skin also helps in Vitamin D production through sunlight.
It also helps to prevent dehydration through regulation of water loss.
When using the forced-choice procedure in measuring odor detection thresholds, the experimenter should separate trial by about 30 second Forced force method an experimental methods which help to obtain threshold.For a single interval and forced choice method there they are at least three procedure for collecting data.
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