Answer: During Puberty
Explanation: Once puberty begins, the body starts to produce different chemicals that activate the testes to make testosterone and the ovaries to produce estrogen.
The femur is not part of the circulatory system because it is a bone.
<span>Schizophrenia was first described by Dr Emil Krapelin in the 19th century. He was director of the psychiatric clinic at the university in Estonia. He first used the term Dementia Praecox or premature dementia and he believed that the condition always had a steadily worsening course or if there was any improvement over time it would only be partial.</span>
Answer:
Oxygen
Explanation:
Your cells use oxygen for energy, as a result makes carbon dioxide
