B problem solver this is correct answer in my opinion
Answer:
Girls have menstrual cycles because girls have changes of hormones in their body. The hormones make the lining of the uterus build up. This gets the uterus ready for an egg which when the egg is released it causes a period also known as a menstrual cycle which happens normally every month for at least 3-7 days.
Explanation:
Answer:
D) four.
Explanation:
The two atria hold the blood that circulates away from the heart. The heart has four one-way valves, which open and close with each heartbeat. The tricuspid valve and the mitral valve are located between the atria and allow the blood to flow from the atria to the ventricles. Also you don't have to but mind marking Brainliest?
Answer:
Whereas a pathological fracture can arise from a single minor trauma to an abnormal bone, a stress fracture is the result of repeated low impact trauma to a normal bone.
