At adolescence, the pituitary activates the gonads which are the ovaries in females and testicles in males. Gonads is a sex gland or a reproductive gland that produces gametes which are the sex cells and sex hormones in organisms.
The blood (circulatory system) carries oxygen to your lungs (respiratory system). Oxygen binds to the hemoglobin molecule in your blood and is carried back to the heart, then pumped out to the other parts of the body.
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