Melanin
A Pigment Produced In The Skin That Protects Against UV Radiation.

Homeostasis Mechanism
A Process Such As Sweating Or Shivering That Helps Maintain Homeostasis.

Umbilical Cord
A Structure Connecting The Embryo To The Placenta For Nutrient And Gas Exchange.

Feedback Loop
A Biological System In Which The Output Influences The Input, Helping Maintain Homeostasis.

Muscular System
An Organ System That Enables Movement Through The Contraction Of Muscles.

Positive Feedback
A Type Of Feedback Loop That Amplifies A Response, Such As During Childbirth.

Excretory System
An Organ System That Removes Waste Products From The Body.

Kidney
A Organ In The Excretory System That Filters Blood And Produces Urine.

Nephron
A Functional Unit Of The Kidney That Filters Blood And Forms Urine.

Ureter
A Tube That Carries Urine From The Kidney To The Bladder.